I used these servos for about 1/2 year, and performance wise, they were awesome. That is if you don't mind loud servos. The 620mg was my favorite, awesome for throttle in a /8 buggy. After using these, I bought a Futaba s9350, and I will NEVER go back. Blue Bird servos are good if you need them in a jam, or for replacements. If you are going to buy any, buy like 3 at a time, because you never know what the quality is going to be like. I've had them last for 3 months, and others for about 2 weeks. it depends. IMO, you should save your money for Futaba or Airtronics servos. They will last much longer and have better performance.