I would say Airtronics are pretty reliable and has high torque – the ERG-VB/VX with 13kg of torque and 0.1 sec, but if you’re looking for Futaba the (#S9451) Digital High Torque Servo are pretty good, have them still…they are 8.7kg and 0.1 sec. last but not least the high tech ones, currently have the highest torque, HS-5998TG with 23.4Kg torque and speed of 0.19 sec
so make your pick