The 300CB is a very good training aircraft.The fact that it doesn't have a governor is a good thing as the new training pilot will pick up the correlation between rotor pitch and rotor rpm.Hover autos and full touch down autos are far more forgiving and theres more room in the cockpit than an R22.
I'm not knocking the R22 its a great aircraft to fly fantastic tr authourity and positively sporty in comparison but better to fly it after you've got around 50 hrs helicopter time under your belt.As for cost the 300 CB is competitive with the R22,(at least it was when I was teaching/training)as it doesn't have the 2000hr overhaul cost.
Hope this is of some help.