Think he's questioning MG90S servos. SG90s are a different beast. All seem to work even the cheap imitations, but not in the case of the MG90S servos and counterfeits.Here's four of'em for 9 bucks.
As I said, I have been running these servos for a LONG time. There is no need to waste money getting "premium" SG-90 servos, there's no such thing. They are ALL generic. Tower Pro is just one of the vendors and there are HUNDREDS of others. This is one of the most popular model plane servos ever made.
But, it's your money.
Nope. Not the same form factor. MG90S servos are a different physical size then SG90 (primarily on how they mount into a fixture such as a Damper). They are not directly swappable.They are all the same form factor. The MG versions have metal gears, which I have found to be unnecessary.