Nashbar sells Sun Race freewheels and cassettes under their house-brand name and the feedback on the 7-speed freewheel is very positive. They don't list the 8-speed version. Bike Tools Etc does list the 8-speed freewheel but they are out of stock right now. Given that both of these companies sell them, i think that's decent support for their adequate quality.

BTW, 8-speed freewheels have always been a marginal item since their extra width puts even more stress on the unsupported part of the rear axle than 7-speed freewheels.

I've used a couple of Sun Race 8-speed cassettes and they are fine. Not as good as Shimano but a lot less expensive.