This is how I see it.
The 92 and 139 are probably both going to be good aircraft once some teething problems are ironed out - on the 92 at any rate, the 139 is too new to know what the teething problems will be. I think the point at issue here is the progression from a crew-change type aircraft to a SAR one.
For example, do the 92 and 139 have tried and tested auto-trans down / hover? No doubt its in the sales brochure but does it actually exist in a certified flying state yet? And does it work reliably? Do they have dual hoist installations in service now?
I am not saying the answers to these questions is "no" but it seems likely that if you are the first to fit the high tech options, there are bound to be problems. Therefore it is rightly considered by some to be a fairly high technical risk to go this way.
Especially if you are the one floating about in the water waiting to be rescued in fog etc!
Of course to remain with existing technology ad infinitum is ludditism, but surely the compromise is to ensure that the kit will do what it says on the label before committing to using it in anger. In other words, if I were the MCA I would have commissioned a trial on the kit before going firm on its use (a bit like BP did with Jigsaw). Effective SAR requires the combination of well-sorted kit and well-sorted crews, and that takes time to develop with new kit, new crews and new (to them) procedures.
By the way Snarlie, the performance issue with the 139 is its range / endurance not its OEI lifting capability - the latter being tremendous (Oh dear that's bound to set Nick off on another one of his rants.......)
HC