Both great games in their own right. Dwarf Fortress stands alone. It's so impressive you cannot describe it all in a sentence. I don't know how to describe all the advances in egalitarian shifts to occupation specialization, psychology of NPC's, community development, emulated physics, mechanisms, entirely random and personal histories, languages, lands, and worlds. It's just sexy. I'm an anthropologist and nearly orgasm every time I have my dwarves throw their ancestors off their green glass lighthouse so their wooden coffins can carry them into the ocean. Maybe TMI.
Minecraft was inspired by DF, but has forged significantly ahead in the economic sector. I'm sure Toady has no issues with it existing other than hoping people donate more to DF so they can keep him alive. However, he SHOULD be charging for DF. It's admirable he isn't, but he should take note. The money minecraft has raked in is promising. We're talking about a non-advertised, independently released BETA that's made over 30 million USD. That is gross mind you; paypal and taxes are hefty but who really cares at that point. The last time I remember a game doing something profitable without advertising was Deer Hunter (late 90's?).
DF would need some tooling. An integrated season-play game mode. Multiple official tilesets, yada yada. Overall polish that doesn't interest the rest of us hardcore. However if an incomplete Beta can make 30 million, what do you think Toady's alpha can garner? Especially with "The Game that inspired Minecraft" as its tagline.