Having been reading here there and everywhere I've decided I do not have a suitable location to use iso 2k so not worth the cost of kitting up for an air mask.
Hi E.D., haven't used many but Upol's one that is commonly available is fine; used that as an intercoat and candy carrier a few times and it's lasted OK and no problem to spray. It's "RFU" - ready to use, no thinning needed.
I've used the Upol 1K clear a few times and it seems to have stood the test of time.
I'm keen to try the isocyanate-free 2K. I have a couple of jobs lined up over the next few months after doing no painting for a couple of years.
I used the upol smart clear for a set of mirror backs, went on very smooth and dried quickly however it does dry a bit dull and needed polishing up after a few days but been ok since. I have some non iso 2k clear to try but not got round to it yet,