Rick,
I've yet to have it chip or flake off...it's a solvent based filler, so I think it actually bonds to the styrene...although the stuff dries really fast (3-4 minutes), it does soften the plastic underneath a bit...but within 10-15 minutes you can sand it without any adverse effects.
It's not a heavy filler like Squadron putty, its got the consistency of melted ice cream... I've been using an old airbrush needle to apply it with good results...it sure beats the old way, glopping in putty with a spatula. Oh, btw, it's a one part filler, so no mixing or anything.
The best part for me so far, is that it hasn't shrunk at all...my Spitfire XIV, which I completed in March, is already showing signs of shrinkage (used Tamiya putty). I've used it on some 1/144 stuff (B-58, Fw-190, Ki-44) and some 1/72 armor, and so far so good...no shrinkage.
Jeff