Thanks for the replies so far. Some good points raised, certainly as far as the $$$ stakes being higher if the exercise is mis-managed.
However, referring back to my original posting, what I'm saying is that the same issues apply for someone doing a turbo-charged piston endorsement as well. Every operator is going to be a bit cagey about some wet-behind-the-ears driver possibly blowing a turbo on his Chieftain, or shock-cooling it on descent, etc. The potential for a screw-up in a piston is no different to a turbine (notwithstanding the cost factor of course). So if someone can make the switch from, let's say a Duchess, to a PA31/C402 type - without any major hiccups - why should the transition from a PA31 to a B200 be as huge a leap as some make it out to be? I think that ultimately, as in all aspects of what we do, it comes down to good training. Lay a strong foundation, build a strong house. Or not, as the case may be...