My solar d771 and d770 have been going strong for a while now. I am not an everyday driver and I tend to go fairly easy on my stuff. performance wise they have been really great. I bought mine back in 2013 and they have been good. I did take a hiatus from the racing circuit for a couple years tho. I was just marveling the other day at how fast the d770 was at the track and that was only with 5.5 volts. but torque was wanting. they def. need HV to be at there best for torque.

I recently borrowed a Savox 1258tg from a friend and liked it so much I bought one for myself. it is double the price but as I notice the slop developing in my solars.. it think the savox will easily pay for itself in the long run. can be found for $50ish. well worth it I think. plenty of torque and speed for most 1/10 apps. nicest servo I have ever owned and at the top of my budget for servos, but glad I pulled the trigger. Star performer.

Ordered a trackstar ts-d99x a while back and still waiting to get my hands on it(slow boat from china). curious to see how it stacks up. good back up for the pit box if nothing else..
https://hobbyking.com/en_us/tracksta...08sec-45g.html