I need a low profile retract servo for my latest project, H-9 AT-6. Been looking at the Hitec model 75, $29.99 at the LHS. They also have a FMA S600 retract for $20 on consignment. Looks to be new, has the original staple in hardware package. Doesn't seem to be any info on the FMA-direct web site. I guess it's been discontinued. The size and spec are about the same as the 75. Anybody have any experience with the S600? Do they hold up as good as the Hitec? Any thoughts?