What will be your pros and contras?
As for me, I prefer DCSS. ToME is just turn-based Diablo, and it seems unbalanced.
I don't know...I have a hard rime choosing as both have interesting classes that have their own flavor.
As for balance DCSS tends to be even less balanced as you can meet worms (!!!) in the early dungeon levels that will wreck you.
I think both games have the pluses and minuses but it just depends on what you are looking for in a game :)
Also, try playing an Ogre Abyss Knight, it's fun :D