There are countless RPGs out there and in particular in the genre of medieval style fantasy with knights and orcs and the like you find a wide selection. Different games are good for different stories and experiences, for different player types, and for different emotions around the table. There is no one size fits all and even The Dark Eye is not some type of super game to end all other games. I currently run two weekly Dark Eye games. One with my original gaming group who has been playing together since 2004. Sure occasionally a face changes, someone leaves town or returns. Between us, we can look back at hundreds and hundreds of sessions of role-playing games. The other group could not have been more different. They came out of the local board gaming club who heard me talk to some people about role-playing games and asked whether I could run a game for them to try D&D (the name they knew). Starting with the old faces. Over the years we had played various flavours of D&D, Pathfinder, Warhammer Fantasy Role-play (including the Fantasy Flight version with all the cards and counters). We had played Shadowrun, various things set in the 40k Universe and occasional off shoots into smaller games like Feng Shui, Anima Beyond Fantasy, Unknown Armies and A|State. We had spent a long time in the World of Darkness, the Star Wars Universe and the Weird West of Deadlands. (I am sure I am missing a bunch of great games here) and so I had more than enough games which are still fondly talked about and those which just fizzled out.
I personally love the following two concepts about running games. Those are choices and consequences. I love it when there isn't the obvious heroic option and the obvious evil option (shall we help the merchant to town or just rob him now that his cart is broken) but instead when things are a little more grey. What if the escaped convict the PCs have been hired to return to custody turns out to be the victim of a local druid who is attempting to enact a dark harvest blessing ritual. The ritual will ensure that in spite of the poor ground the harvest is large enough for the local village to get through the winter. The druid carefully chose someone whose life was already forfeit, but might be dealing with dark powers. Without the ritual though it is highly likely that not all people will make it through the winter. Now the players have choices to make.
Closely linked to the above you have consequences. The players, through their choices impact the game world and change things. If they return the prisoner(s) then maybe their reputation rises, they gain an appointment at court are sent out to escort some diplomat, but they will also hear of the harsh winter and its effect on the village and see its effects if their journey ever takes them back. If on the other hand they allowed the ritual to complete then maybe they are no longer welcome at the court, but have made an ally in the druid who informs them of a growing imbalance in the cycle near a village beyond the mountains.
Having spoken to my players I asked them what were the best bits of the various fantasy games we had played and the response was. "We enjoy the game best during the very early levels, where mundane things and normal people are still challenging and dangerous."
From the above point of view, and the fact that one of my players hates particularly swingy skill checks, I settled onto the Dark Eye and pitched it to the players. I sold it to them as a grounded, slightly Germanic feeling fantasy game, which did not focus on constant fights, but rather social interaction and player choice. A game where the character would still be heroes, but where if the city watch came out in force, they would still be able to arrest the players. A game where even after a year or two of weekly sessions, the local Baron was still going to be a force to be reckoned with. A game where player characters could seriously hurt themselves falling out of a tree rather than getting to the point where they could just jump off cliffs and just shrug off the damage. A game where a close fought fight means the party will likely need the best part of a week to recover with access to healing herbs and medical care. A game where likewise, if you blew all your power, a wizard or priest would need some days filled with prayer or meditation before their powers would return to have them at the maximum efficiency. But also ultimately a game where they could still also be good at things, and be relatively assured that if they wanted to build a character good at say riding horses, then that didn't mean they have a 60% at failing a ride check rather than the more normal 70% (WFRP, I am looking at you).
We are now in the 4th of year of that campaign. Easily the longest game we have ever run (Pathfinder Kingmaker campaign previously held that title) and yet people are keen to play more. My beginner's game is in the 2nd year of the campaign and there is also currently no desire for anything new. At various key points I have been asking whether people wished to continue doing this, and so far the answer has been a resounding yes.
So what do they like so much? In the main group we have played from 1100 AP to around 1550 at the moment and so people have not only seen their characters at the beginning of their adventuring career but could also shape their growth. Things which were problems early on (such as crossing a medium river) are now trivial because enough characters are simply good enough at the sort of the things required.
The freedom to spend your AP in any direction means that characters can develop in unexpected directions. People can look at their character sheets and look at some odd choices and remember what happened to them that made them invest points in pottery, or piloting a raft, or the like.
While many people call The Dark Eye a "crunchy" system, once you have worked out how a skill check works, you have pretty much got everything in the game down. Want to cast a spell (same mechanic), want to fix a broken wheel on a wagon (same mechanic) want to work a miracle in the name of your god (same mechanic). More detailed mechanics exists, and what I find fascinating is that you can have different people use different levels of those optional mechanics. Say most PCs, if they hunt for food might make a single dice roll, say roll survival, each quality level feeds one person for the day. But maybe you have a hunter in your group. Suddenly to them at least, the hunt is something that really interests the character. They might look for nearby tracks, find a good ambush spot, sneak up and hide themselves and when it comes to it, take the important shot. Role-playing that hunt might take 5 to 10 minutes at the table, but then that player wants to be a Hunter, and you have the rules for that, if you want them, completely optional. Next they love the game balance. By that I mean, magical or mystical have cool powers that are super useful, at times, but don't dominate the game. The mundane characters are often the star of the show, and they don't require powers to become interesting or have their own spotlight moments. Then they love the consistent game world. From the fact that super many people have names that are derivatives of the twelve gods over the fact that once you have a feel for the world, then in most situation you can actually use your past knowledge to assess whether something is probable, possible or outright something that requires major supernatural powers. They love that if there are rules which govern them, then by far the majority of the time the same rules apply to the opposition. That means that whilst they can't one shot kill people most of the time, no NPC assassin will likely just one shot their character. They love that many problems are of their own making. They unmask a conspiracy and shame a major player in local politics, and then suddenly that faction might send agents or worse after them. They interfere in a duel and make a certain knight look bad and that knight might show up a year later looking for revenge. I admit that is of course not in any way unique to the Dark Eye, the fact that the game world is well described and has understandable politics means it is easy for me as the GM to pick situations where some of these old things can come back to bite them. The pre-written adventures often have a number of avenues on how the PCs could be involved in the action, and so I can choose the one that will give us the most juicy conflicts and stories. So my players are currently literally trying to get out of a large hole in the ground, and once they have dealt with the current situation and the political ramifications, they might head northeast to some snowy forests and see why the drum they heard about a couple of years ago is causing strife in the city of merchants. That will be another point where their current arc of playing politics and intrigued in the Horasian Empire is over and might lead into the well regarded and somewhat epic Theatreknight campaign. I cannot wait.