I would have thought the best training helicopter is determined by what the student expects to fly next.
So, although the R22 was never designed to be a trainer, it may be the default consideration for someone progressing to R44/R66/B206.
The S300C makes sense for most other US helicopters (MDs, Enstroms, Bells, etc) and the G2 for most European helicopters (ECs, Gazelles, etc).
The little Cabri may be the future, but they owe Sikorsky a huge debt of gratitude for their dereliction of duty to the S300. The 'C' in particular is still a 'world class' helicopter.
Mind you, that may be what also prompted Enstrom to develop the new TH180.
