Everyone slating them for not lasting too long, I got mine second hand after being used for a year (I'm very cheap) and It's just recently konked out after 6 months of use..
I don't see that being too bad for a freewheel used for trials, given the amount of force put on them.
They're not going to last forever, but they'll be reliable until they do die, and I'd rather have a season on a freewheel I can trust rather than a few years on a freewheel I'm not too sure about.