Has anyone any experience with iMatch to say whether its profiles are good or will an upgrade be necessary to get an iProfiler license?
iMatch delivers good profiles.
The differences between those made by both of them would be unlikely to be visible on most prints, except by the most critical of viewers. In isolation I doubt anyone would would be able to say which was made by which.
Profiler (or PMP) becomes important when you want to use autospectrophotometers and build profiles on a commercial scale.
The other advantage is being able to use custom sample sets to target any specific colour ranges* and refine some profiling aspects eg monochrome, but those uses really are the absolute finnesses of profiling.
iMatch really does a very good job for the majority of cases without having to spend silly money or learn arcane command line instructions. You don't always need to have the latest and most expensive kit or software to deliver good photos.
*I think if you trawl the web you may even find some hacks to allow iMatch to use different target sets. I'm not convinced it's really worth the effort though.