In my experience, with light recoiling guns accuracy is not hindered. With more recoil, the simulation is not the same as when shouldering, using a bi-pod, or rests, from which the tune not the same. With heavy recoiling calibers, they jump the front straight up with no rear word movement, and is why. With magnums, I get large POI shifts/changes between a sled and a bag/rest.
Where I do use a sled is for barrel break in, initial sight in, velocity tests, etc. with large calibers, then I switch to the other methods for final adjustments, load development, and regular scenarios.
For me, they have there place and time, and I do use mine some. Glad I have it for those few scenarios and some of those heavy recoiling magnum hunting guns I work on.
Donovan Moran