The upgrades are substantially less worth it if you're a wheelchair user. Particularly on a Voyager.
Same chair in the same design space, same inglorious isolation from anybody with whom you're traveling, the door still retracts into the wheelchair space so you can't lean back, diesel and toilet exhaust goes up behind your back so hot and smelly,
The XC 1st Class food offering doesn't excite me. And there's something that particularly irks me about the insubstantial metal-filmed plastic cutlery.
The XC HSTs on the other hand, are to my experience the only HSTs with a usable 1st Class wheelchair space and accessible loo