Yes, buy them, save your money. I have used the HXT5010, which are the same as the TowerPro 5010. They have great speed, and torque and are about half the price of the standard name brand servos(Hitec 311) and have ball-bearings too. The Hextronic 9g servos are a really good buy too, use them up to as Switch said, about 1.2 kg and you are set.
Have fun,
Curtis