Personally I really liked the writing in the Avernum series too (although I've only played the first four games). The gameplay style is much more tradiational, similar to the Ultima series, with a party of heroes doing some adventuring. But the subterranean world is really interesting, and it the games have some of the best writing I've seen for a traditional role-playing game.

You won't find the tough moral dilemmas of Geneforge, but you will find an excellent and unusual setting that's really well fleshed out. Might be worth a look, although as I mentioned earlier in the thread, the first 3 games are older than Geneforge and have even simpler graphics and clunkier controls.

By all means play the rest of the Geneforge series, though. Actually I've only played the first three, now that I think about it... I should try the rest.