it has a MediaTek cpu from 2009 (ARM), which is a bit slow, but has a pretty nice set of features. here is a complete design/data sheet:
the market is currently flooded with phones using this cpu, which is actually a good thing for people in general, since they have the option to buy something "simpler" and not spend a lot of money on products from the leader manufacturers.
the android os itself (2.x at least), is quite well put for the end user, i must say - with a lot of options and good looking interface. as a more "low-level" os user, i might actually need something a tad-more in the lines of root access for the os, yet in the same time i'm quite tired of editing linux configuration files...editing configuration files on a modern os i think is usually a bad (or flawed / incomplete) design and unfortunately this is the case every time i install a modern linux distribution. actually this has been the major reason i slightly prefer windows, even for programming, while it's lacking a library / package manager or the idea of a such. obviously a very subjective matter, of course.
on the topic of stability, i've found one bug so far, where in a certain scenario you need to restart the device before using the android market, since it says "no space available", even if there is space. that's not a big issue though and hopefully nothing else comes up.
as far as my current cell phone goes, i'm still rocking an old nokia from 2003. i guess i mostly use phones for...well - answering calls and calling people.