I have a set for a future build and castings look really good. The springs/retainers should be good for a hydraulic cam with around 0.500"+ lift?
The pros of these heads:
#1 - They look like a stock head (no other aluminum head does.)
#2 - They fit like a stock head (straight plugs allow using manifolds or headers designed for stock heads. The angled plugs of the Edelbrocks can cause problems with headers not designed for the angled plugs.)
#3 - Cost and performance.

The cons:
#1 - I guess they are not made in the USA?
#2 - The large diameter chamber needs a larger bore size head gasket?
#3 - Possable quality issue on some early heads? (just to be fair, my Stealth heads castings looked better than my Edelbrock Victors, and I did crack the Edelbrock heads, so any company can have problems?)

I also know of at least three people who have been running the Stealth heads for a year or more with no problems