I've got one bike which has shimano 8 speed STR500 shifters and a mix of derailers, and two bikes with 9 speed groups (1 Dura Ace, 1 Ultegra) and I don't see myself upgrading any of them unless something breaks. I've been very pleased with all three sets of shifters.

I honestly can't say I've ever owned 10 speed brifters, or done more than test ride them so I can't speak to the weight or performance.