ORIGINAL: JeffH
The only downsides are, current draw and the fact that your servo will not last as long. The motor will always be pulling against the spring.
I'd agree for sure with this. But interestingly, on a different thread regarding optical cut-offs, one veteran gasser flyer has said he plans to keep the return spring on from now on, just in case of linkage failure. Not sure if the spring can pull a 'dead' servo, but if it can perhaps he's also guarding against a failed servo.