Well, more for me to huff, I guess!
I haven't started using these yet. I've got a bottle of Micro Weld coming next week. I want to use them all on a cheap model I've got here and see how they're different. It's a snap-tite I'm gonna sand the nubs off of. Can't decide whether or not to scribe the panel lines or not as they're raised...
But the viscosity of each as well as the application has to be different among them. Some directions say to squeeze the parts together until the plastic fills the gap. Others leave it up to you to fill later, which I plan to do with some new-to-me filler Mr. Surfacer.
Interesting about the Legos. I used Testor's glue on my Legos as well, but it wouldn't adhere to anything. It would kind of fill in the gaps but wouldn't hold anything in place, so when it broke apart, the legos weren't ruined.