(Speaking from my perspective here, starting to do so before some of the other perspectives that have now ninjed me.)
I can't say I was anywhere near the first release time... 23a, I
think was the particular vintage of my introduction (although at the time I wasn't minded to note exactly how late I was to the party). At some point between then and now there was one
particularly efficacious improvement which meant that on the same computer as before I suddenly found the dwarves fair on
zipping around the screen (and they haven't stopped since... well except for my frequent pausing during micromanaging functions[1]), whereas before they'd been toddling along at a much more watchable rate.
When first I ran worldgens (which I did a number of times, even before I got to play for real... I laugh to think of this now, but I was revelling in the worldgen graphics several times without even considering diving in deeper), I'd set them running overnight. Hardware has of course moved on a little (I'm not using a
top-end machine, even now), but my tendency to go for maximum-sized custom worldgen parameters (tall, as well, if that matters) seems not to hinder the modern worldgen anything like as much.
(There's been added complexity to the worldgen... the whole thing with fields, etc... And yet there was also a re-abstraction of populations (saving for the more notable figures), which sped up what had started to lag again with all the additional features being added to the population movements.)
@MrWiggles: Heck.. It's not even released in
2013 as complete.
[1] And
re-pausing when I accidentally hit the new-fangled (f)ollow button on a dwarf, when I mean to press the "g"-key... It's a somewhat useful new addition, to keep track (of friend and foe alike), but it does somewhat beg a split-screen approach so that a tracking side-window might be possible even while the rest of the management functions are accomplished... Sorry, didn't mean to lapse into "wish listing", here//