I have been using a 50 year old disc/belt sander which is finally vibrating and tearing belts. I was looking to replace it and in the Grizzly catalogue there are two identical models, but one is 1750 RPM and one is about 3500 rpm. They are both direct drive, so the motor itself is slower on one model The slower one is a bit more expensive. ANy recommendations? Why would one or the other be more advantageous? I would imagine a hgher risk of burning on the faster one. Thanks for the advice.