HeloTeacher
I operate 300C's with a school that operates R22. All the students who have tried both have always gone with the 300.The most common Reasons stated being
a) It is bigger and more comfortable inside
b) It is more forgiving and easier to fly
c) There is always plenty of power in hand
d) Students never hear anything bad about 300's ie mast bumping and more R22's seem to crash through pilot error ( before everyone jumps down my throat remember perception is very powerful )
All the above is dispite the price being 10% more expensive. However I generally find that a student learns quicker in the 300 so actually from his point of view it is the same price.
As for relibility and cost I would have to say they are about the same ( based on my 300's flying about 400 / 500 hrs a year )
300 uses 3 gal more fuel but does not have a massively expensive rebuild every 2200 hrs or 10 years If you actually factor this in it makes a big difference to your DOC's
If you really want to go cheap pick up a 269B ( £ 35000 ) they have huge lives on components and the purchase cost is very small and like the 300 cheap to insure against an R22 ( this should tell you something about the R22 as a trainer, insurance companies hate paying out, so stuff the R22 with much higher premiums )
Hope this helps, for more info e mail me and I will provide you with a phone number for a chat as my typing is too slow
Have a safe one this year everyone