It's an old thread, but I'll chime in. I used Ultracote for years after finding it easier to apply than Monokote. Every plane I never did had sagging covering, wrinkles, and lifted seams pretty quickly. Mind you, I fly in Texas so the summer heat is pretty harsh. I've even had seams lift on the first day out. Yes, I do get dust off and clean the covering before I stick down another layer. I was tired of having to repair my covering job after every day of flying, so I tried Monokote again. I covered a classic pattern plane, which I fly a lot, back in the spring. I ironed down my first lifted seam this month. Maybe Monokote changed back to their old formula, or maybe Ultracote is different than it used to be. But the performance speaks for itself. The only downside is that the Monokote doesn't stretch as easily.