My TAFE uses a strange combination of machines. The old more general campus that I used to go to last year had in what I presume to be an audio engineering classroom (though I'm not entirely sure) 2011/09 era 27" iMacs with decent specs (16 gigs of ram, 1 TB HDD, Core 2 Duo/i7 depending on age), until mid way through the year replaced them with maxed out 2014 models.
This year however, my class moved to the TAFE's art campus, and it's a lot less consistent. The classroom I'm in has a collection of 2008 24" iMacs with Core 2 duos, although they also have two class rooms with 2011 era iMacs. There's also a small room with a few Lenovo systems, and 1 or 2 older iMacs.
Otherwise, the tafe generally uses/gives the staff Lenovo systems that are more in line with what my highschool uses, but I have also seen a few dells, an old cheese greater Mac Pro and a custom built PC around sometimes though.