Yea, I did some more research - Model Master is a Testors brand (which now belongs to Rustoleum). I'm guessing the black label Model Master was more or less the same as Testors 3507 and Testors simply decided to stop competing with themselves. But here is were it got really interesting - Hobbylinc shows Testors 3507 as now discontinued - replaced by Testors 281216. I was placing an order from Hobbylinc anyway so I added a couple bottles of Testors 281216.
The really interesting part? It showed up yesterday - and the card is labeled 281216. But the actual glue bottle says 3507
I still have a little Model Master stuff left, I'll have to see how this works after I run out of Model Master...

BTW aeopav - it's the combination of viscosity (thicker than the pure liquids) so if fills gaps better, it glues most plastics well, and that applicator tip is perfect for making sure you get it just where you want it.