I just started using the BlueBirds in my T4. So far I am happy with it. Had to turn down the D/R cause it was a little too fast. The truck turned in so fast, the rear wanted to keep coming around. I've only had it in for about 3 months now, so I don't have too much use. But for the price I am very happy.
I run JRz9000s servos on all my 1/10th scale cars and trucks. I run JRz9000t on my Losi 8ight. I recently let a guy at the track borrow a JRz9000s when his standard servo gave up. He was running a Losi XXXT MF1, he said it was a completely different truck and he never had so much steering before. Guess what? He no has a JRz9000s of his own.