I have 2 and they both have always acted less than perfectly.  If I'm very close to the dust collector they work fairly well, but any distance, such as 12 feet and it's less responsive.

I pulled it apart and it has a very different battery.  I didn't test the battery but as it's always acted this way since new I don't think that the battery is the problem.  And as I said, the turn off works pretty good.  Only the turn on is questionable, and on both of them.

Now that I've taken it apart I've encountered a new odd problem.  With the cover off (which is plastic) it seems to work.  Put the fob together and it won't turn on.

I saw a European site that sells clone fobs for garage doors and other things,  they have the same appearance as the Grizzly fob.  There are 2 main buttons and 2 little auxiliary buttons that seem to be for cloning or programming.