Guard infantry got better, overall. Conscripts look pretty good if you include a commissar and a priest. Stormtroopers got more reliable, etc.
I think ratlings look useable, but they don't do enough damage to make them especially good at killing characters. This is true for all snipers, though.
Ogryns are disappointing, frankly. Really wanted to like them, but I don't.
The tanks look a lot tougher, but I'm not convinced their firepower justifies their cost in most cases. The Hellhound looks good, the Hydra looks awful, etc.
The thing that came out best is probably the Taurox. Looks better than the Chimera at this point.