I find myself wondering, if not the Robinson products, then what?
IMHO, it depends on what you wish to achieve. If you are preparing for a career as a helicopter pilot (except for instructing in Robbies) , it may be to your advantage to do all of your training in a turbine helicopter, as you will accumulate significant turbine time as part of the process. Even if you are not training for a career, it will be advantageous to train in a turbine helicopter if that is what you intend to fly after your training is complete.
While not intending to pursue a flying career, I did virtually all of my training through the CPL-I level in an Enstrom 480B and am presently working on the CFI-H in the same acft. Yes, its more expensive than an R22 but not a lot more than an R44 which even Robinson says is the preferred acft for training. And, the 480 is probably somewhat less costly than the 206.
The Enstrom line of helicopters are under-appreciated IMHO. I have owned a 480B and a B407 and believe the 480 is one of the best kept secrets in the helo world. Enstrom is said to be doing very well these days with a strong order book. The 480, as many here may know, was originally developed as the TH28 when the U.S. Army was soliciting bids for a new training helicopter some years ago. Bell won this contract (even though, it is said, the TH28 was the only bid which met Army requirements) so Enstrom "civilianized" the TH28 into the 480. Several governments around the world have recently selected the 480 as a military trainer. The 480 safety record is superb.
Every choice comes with tradeoffs. Cost is only one of the issues and in the fullness of time the cost difference between training in a piston helicopter and a basic turbine helicopter may be insignificant.