I have a Level 50 Wizard in Puzzle Quest (for the 360), making it only my second CRPG character (ever) to reach a level cap, joining my Level 50 Ice/Ice Controller in City of Heroes. I'm not much of a fan of RPGs, and I've espoused this many times before, but Puzzle Quest and Mass Effect have both ensnared me. There are three major things that bug me about most CRPGs: 1) Fantasy, 2) Analysis Paralysis, 3) Grind. So far, Mass Effect is the only CRPG that has ever managed to avoid all three pitfalls in my mind, automatically awarding it the grand title of my favorite CRPG ever. In detail:

Fantasy
Most Fantasy just plain bores me, especially Tolkien and his millions of followers. I just don't have much interest in it. Mass Effect is Sci-Fi, and even bad Sci-Fi entertains me. Mass Effect's plot pattern is a common strand in Sci-Fi (in games alone it's very similar to FreeSpace's plot, just with more alien species and less dogfighting). I played City of Heroes as much as I did simply for the comic book world and some of the socialization aspects.
Analysis Paralysis
I'm not a number muncher, nor an Industrial Engineer. I don't really care to sit down and plot out my strategy in Excel before committing to a course of action. I don't want to spend a lot of time fretting a decision and I certainly don't want any decision I do make to handicap me from playing the game. Puzzle Quest as a "casual" CRPG didn't have this problem because there were fewer choices. Mass Effect doesn't have this problem because it lets me throw a lot of that stuff out the window. I don't care to micromanage the game. I'm happy letting the game auto-allocate skill points to my squad members and more often then not I go with the auto-allocate for my own skill point expenditures as well. I'm not even paying attention to what "level" my character is at anything in particular and frankly wouldn't know at any given point playing the game... I'd have to open up the menu to find out. Honestly, I love that the pop-up numbers are short, sweet, to the point, and only in a very easily ignorable corner of the screen and the menus. The skill point window is nice too in that it lists the nice upgrade bonuses that show up later in the track, helping me gauge specializations.
Grind
I've found that I don't like turn-based combat, at least not as it is in your common CRPG. It bores me. Puzzle Quest escaped the grind by swapping turn-based combat for a Match-3 game, which is the sort of grind that I actually "enjoy". Mass Effect's real time combat is pretty satisfying. I like the almost FPS, but with amazingly easy aiming thing and game pauses while I switch weapons.

I'm very much enjoying my explorations in Mass Effect and it really is my new favorite CRPG.

Also, some people hate it when I make this comparison, but Mass Effect really is Super Advent Rising RPG. Unlike some people, I actually liked Advent Rising and Mass Effect is everything I liked about Advent Rising but (much) bigger and better.