I have played quite some MUDs since now, and Dawn is somewhat special.
First, the character generation is _VERY_ detailed, and the chances of developing your character are enormous. In fact, in this aspect it is the best MUD I ever saw. I created about a dozen characters now and can say that everyone demanded for a totally different playing style, so everyone should be able to create a chracter he likes to play for a prolonged timespan.
The immortals are nice and polite, and if you ask for help, be sure you will be aided:)
There are some stock zones, among them the beginner town (the infamous Midgaard;>), but also a lot of custom zones that are unique and detailed with a good deal of atmosphere.
The religious system employed is very detailed and even affects your character, e.g. a cleric will gain a few basic spells and skills, and a number of others based on the belief he adheres to.
However, with all that good aspects, a bad thing about dawn arethe players. Not all of them, however. In fact, most of them are friendly, kind and helpful, but then there are some that could be best described as grief players that don't care about the person on the other side of the screen, playing a MUD-based counterstrike, often to the point of unfairness. Sure, you can stay out of PK completely, but then you miss the Clan system as a whole.
All in all, Dawn of the ages is one of the best MUDs I ever visited, and one of the few that made me stay for a longer time. If you are bored with your current MUD or are looking for one, give it a try, it's worth the effort.