Check out this thread: http://www.garagejournal.com/forum/showthread.php?t=237844 Lot of good information there. I have the Eastwood pressure pot and when it works, it great. When it doesn't work, I would like to beat the hell out of it with a sledge hammer.
I'm going to spring Carlisle this year and I am going to check out the BRUT sandblasters in person. I hear good things about them.
I have an indoor ALC unit and and outdoor ALC unit. Both are great. I've burned atleast a ton of coal slag through them, with the only issue being the aluminum gun on the indoor unit wearing out.
I picked a pressure pot blaster at yard sale. Likely HF brand but it works. One thing I do is sift all sand to avoid annoying clogging. Always seem to find some oversize chunks that would clog valve. Do my sandblasting in wigwam