Re: js100 and the mo joe
The Mojoe will hold it's own and it would most certainly represent an upgrade.
It has the same professional build of the EVO's in the JEM. The Mojoe is a clear and articulate pup that will give you Satch sounds but can also do lots of other stuff too. Playing with your amp settings or an external EQ will give you any metal tones you need as well.
You might also want to consider Breed's, which I believe Vai has in his Basswood guitars, or some of the John Petrucci pickups depending on your playing style. Those are on the same level of build quality and are really just different flavors of tone. It all comes down to what tones you're after. If you play a lot of Satch, I'd go with the Mojo or Fred, no question.
In any case, upgrade from those Axis pos's.