In Vertical magazine from December 2003, there is an comparison of both types, I have it somewhere as an pdf file, I'll send it to your eMail when I find it.
Now, from what I know, it's easier (and cheaper) to train initially in 300, and then go for R22, than the other way. Plus the 300 is a bit safer machine. But that's the case if yo want to fly both.
Right now there are more Robbies flying around, and many operators fly the R44, so if you're thinking about a job, then going through the R22 only, than R44, and than a turbine will be much more effective. At least that's what I figured out
