Badger is likely the most popular disposal choice. For what it's worth, if the motor is froze up, the hex key will take some effort to turn though what it is hung up on. I'd try to do a visual check with a flashlight to see if you can see the culprit. The only other possibility is the motor lost a bearing. I would think you would have heard it squeal to a stop if it were a bearing gone bad. WARNING!! While trying to turn the motor with a hex key, make very certain the power is off.
I moved into a rental when I was a big kid. The disposal didn't work. It would hum for just a bit and then pop out it's breaker. I worked with the hex wrench for quite some time before it finally chewed through all of the dang mop strings that is had chewed into and then stalled. It ran like a charm once it would freely turn with the wrench.