I've just changed from the 300 to the 22 mid way through my CPL training.
The 22 is a twitchy f%cker
, and after the first hour I felt like 45 hours ago when I'd jumped into a chopper for the first time from the plank. The 22 seems to require much faster cyclic corrections than the 300, but has the same lag in the reponse, so while you're learning to get the timing right, the oscillations are like when you first learned to hover.. I'm getting the hang of it after two hours in it, but I suspect it'll be another one or two at least until I feel as confident as in the 300.
I would absolutely recommend everyone to train on at least two machines, including the R22, it would have to make you a more versatile and thus better pilot.