I, too, had a model ruined by the latest incarnation of Micro Flat, which, like the ones mentioned by everybody else, turned milky opaque. I have been using Microscale products for twenty years now, and never had a problem with any of them, except the clear coats. I remember back before acrylic paints became popular with hobbyists, Micro would change their clear-coat formulas, it seemed, about every six months, and none of the new formuli were compatible with the previous ones. So you had a big mess trying to figure out which was which. I seems when it comes to clear coats, this fine company is snakebit. I also remember a beautiful Monogram F-105G Georgia ANG bird I built (adding Microscale decals) being totally ruined because thier dullcoat was so sensitive to humidity it clouded, beaded up, and did every bad thing a clear coat can do. It seems these varnishes could not be used in Houston's sub-tropical climate.
So, since I have no access to Gunze-Sangyo (dammit), I use Testors for all my clear-coating duties. It may be a bit thick, but at least it's tried and true.
Tom