Weaver and Sightron basically use the same idea for tracking....just in reverse of each other.
The T-series Weaver tracking stystem uses carbide balls on the w/e adjusters plungers that bear against the erector tube. This gives a constant surface contact area as the w/e adjustments are made. Sightrons ExactTrack system uses flat ended w/e adjusters that bear against a carbide ring surrounding the erector tube for a constant contact area.
The Weaver optics run from okay to very good....luck of the draw, it seems. The SII Sightrons optics are more consistent from scope to scope and are as good as, if not better than the best you'll find in a Weaver. The Big Sky series 36's do use a bit 'better' optics....but in back-to-back testing with my SII series Sightrons I'll be darned if I could tell any difference. Testing was on a sunny day...overcast could be another matter.
Both scopes have locking rings on the A.O.'s....except for the early T36's. I believe the Sightron loads the objective lens a bit more than the Weavers do.