First of all, as a contractor I feel your pain about job site theft.
No matter who took your grinder, I hope you find out who it was and
beat him to death with the same grinder.
For a grinder used as a sharpener or reprofiler, I think slower is
better. A less aggressive machine is always a good idea on a cutter
as you can easily burn the metal or take too much off.
Most of the guys in the woodturning group I know use this one,
or same link if the wrap munges:
I have two, and one I have had for about 10 years. The wheels are
good, not great, but certainly serviceable. Be aware; they aren't
Norton type wheels. You will need to true them up.
The good news is the oldest grinder still runs like the day I bought
it, and the original wheels last a really long time. Some of the guys
in the club still have the same wheels that came with the grinder
after years of moderate use.
This one is easy on the pocket book, too.