I think I stumbled upon DF some time around 2008 (0.28.181.40a I think it was). I don't know who or what tipped me off, could have been that I happened to read the 2008 Gamasutra article and got interested? I recall it was just a lucky internet accident with wonderful repercussions (hmm, a negative term according to dictionary, but I think that suits DF quite well)!
I have a history with ASCII games, I've been playing around with NetHack since 3.1.x (I think? wow that's 20 years ago...) and played Adom quite a bit too. In general, I appreciate the simple informativeness of ASCII.
I remember having tried a DF tileset once, didn't quite like it because it was... ugly
For me the tilesets look ugly because they try to look "better", but really aren't that fancy to look at after all. ASCII, on the other hand, doesn't try to look good, it just tries to convey you the info on the screen in the most convenient and efficient way and that's enough for me
I think all those dots, quotes and letters have burned into my retinas for too long now that anything else in DF would look just plain weird.
Think of it like this:
"What the hell is that purplish white and red blob with small legs... is it six legs... is it some kind of a slime or an insect, what the heck??!? OUCH, it bites!"
vs.
"A small purple "x"... it's a grid bug! Smack!"
PS. Also my kids seem to enjoy looking me play ASCII DF. I consider that quite a miracle, seeing as they've grown into all this High Definition Ultra High Detail World with fancy graphics and lens flare... "Dad, where's that cat now, wasn't it a small gray c? Oooh, there it goes! Ow, it's there with the small green g's, why is it all red?"