I've had a chance to take a look at the Buffy and Angel RPGs now. IMHO, they're wildly overpriced for the content delivered. Since this matches my experience with Eden's non-licensed games, I don't have high hopes for Eden's Stargate RPG, if any is forthcoming, to be any better.
IMHO, the key factor for me in deciding if a licensed RPG is worth picking up is "would this still be a useful sourcebook if I used a different set of rules?" AEG's Stargate is one of the licensed properties for which this is true - I'd pick up the books even if I was going to run the game with a completely different rule system. Can't say the same for Buffy and Angel, unfortunately.