Dragonrealms was recommeded as without classes, purely skills-based role-play. It isn't, but it is, for me, engaging. This may, to some extent, be the age of the players, which I suspect is rather older than on World of Warcraft in general (certainly from the comments I saw). That works on two levels: I don't feel uneasy when people say "I'll be in late tomorrow, I've got detention after school" and, like in so many things, being older gives you a reasonable chance of being more skilled - certainly more skilled at role-playing. In Dragonrealms everyone has access to the same core skills, but your character class (the guild you join) affects how quickly your skills progress. Every class has a primary, two secondary and two tertiary skill sets. Each skill has a series of wall ranks which are harder to learn. For tertiary skills that's every other rank, for secondary every four ranks and for primary every eight ranks. That isn't the only place that the class makes a difference. If you are a warrior mage, you get access to a special set of spells, as do moon mages, priests and so on. A ranger gets a different range of spells and a couple of special skills. Thieves get special skills, as do barbarians.
I'm rather surprised to say the Dragonrealms is my first ever MUD. MUDs, if you're not used to them, are text based multi-user dungeons. The interface describes the room, you interact by typing, for example typing look will let you look around the current "room" and see what's there. The space is divided into "rooms" (they can be a forest glade, a street corner or a room in a building or dungeon, hence the quotes). They rely on some smart text analysis, which can be a little frustrating.
For example, the difference between aim rat and target rat? In spoken English the two phrases are the same. In Dragonrealms, aim rat is for a missile weapon, target rat for a spell. Speaking as a warrior mage (I tried a ranger briefly, but it wasn't for me, warrior mage seems far more pleasant, but that's only my opinion on a dozen hours or so or playing and may well change) when I see a critter (I'm still hunting rats, not monsters at the moment) I will prepare a spell, aim my crossbow, target my spell, fire my crossbow, get melée weapons ready, cast the spell, engage in melée and as my spell-casting regenerates I will prepare, target and cast the spell around the dodging, parrying, smashing and slicing of the fight.
Will Dragonrealms ever become my primary way of spending my free time? No, almost certainly not, but actually that may give it longevity. Dipping into Dragonrealms for a couple of hours, then going and doing other things means I can advance my skills in Dragonrealms and the grind (even though I've spent a fair bit of time added up killing rats) is less of a drudge. The combat system, even if using macros to trigger the actions, is rather interesting - wounds accumulate, scars too and slow you down. There is also a "balance" factor to bear in mind, and fatigue, so rather than falling into a cycle with each fight (and despite what many of the websites suggest) you can, and probably should assess the situation. Do you need a move that restores your balance more than harms your opponent? Is your opponent close to death and can you afford to be off balance to finish it and recover before the next one arrives? Maybe these subtleties are there in World of Warcraft, Oberin, Dofus and the like, but I never found them necessary. That said I do miss scouting the area visually and choosing the tactics of approach that World of Warcraft offered, although I'm still doing the real newbie things, and that layer of subtlety might come along later too.