Tower Pro ESC's work very well for their price. Their quality IS lacking, however, compared to better brand names. It's obvious if you look at the soldering and manufacturing of the components. Precision doesn't look as if it was a main consideration during production. However, regardless of that, they work, and very well at that. I've used two Tower Pro ESC's and they both worked fawlessly.
As for their servos, they work well but their resolution isn't very impressive. As I mostly fly helicopters, the servos are simply not smooth enough in their control for my purposes. I do use them in my park flyers though where smooth precise control isn't as important and they work great there.
As a side note, (may aswell add a shameless plug here
) I will be carrying both Tower Pro and Dynam speed controllers, (Both are very cheap, Dynam ones look much better in quality though). I've got Dynam in stock right now, TP will be in stock in a few weeks. Currently i'm one of the few retailers in Canada carrying them, so if any of you Canucks (or yankees!) don't want to order from Overseas, let me know
.