I've had my SPC pro-lite uppers with Howe tall ball joints on my 3780 lb G-body for 4 years now. Been aligned twice. No galling, no bending, happy as heck with them.
Have yet to see any proof of "multiple SPC failures" other than several members on this forum who talk about it repeatedly but never produce pictures, links or direct references. You would think if they were really that dangerous, in a world where everyone has a camera phone and internet access, pictures of these failures would be everywhere. A UCA failure is pretty catastrophic... you're going to have some significant damage and pissed off customers. There was a failure on pro-touring at the end of last year, the guy had a 1st gen Camaro with Guldstrand mod and the upper arm was installed backwards as well. All the arms to contact the frame... induced bending loads and eventually failed. It was ugly, no doubt... but definitely an installer issue.
Ball joints pretty much always end up installed in plates. Look at how the new G-body Ridetech arms are... plates with bolted in ball joints, welded to a tube. It's obvious that the SPC parts aren't built to be the brick sh*thouse of control arms, but they aren't junk either. Internet postulation of "these look weaker" is not evidence. Any time you mod a car, you mess with the factory engineering... suspension geometry, driveline angles, frame clearance, etc... if you don't look at it with a critical mindset, check everything, and validate safety, the installer can make plenty of errors that cause parts to fail.