Pretty much, none whatsoever.
Glastar actually manufactures both machines. The CrystalMaster Pro and the Glastar B12 are the exact same grinder in the variable speed. Both have a 1/3HP direct drive motor and work with our magnetic diamond disks.
The CrystalMaster Pro comes with the steel wheel head for attaching our magnetic diamond disks to and the B12 does not. This is main reason we offer the CrystalMaster Pro instead of the B12. With the B12 you have to purchase the steel wheel head separate from the grinder. Just one more step that confuses things in our opinion.
The B12 is also offered in a fixed speed model with a 3/4HP motor, but we do not offer this model as it is harder to use to obtain an adequate polish on your glass. We've also never had anyone bog down the 1/3HP model in day to day use, so we don't feel that a 3/4HP motor is necessary for this size machine.
If you would like a quote on the fixed speed 3/4 HP Glastar B12 grinder with wheel head, just contact us and let us know and we can quote that machine for you.