While I agree with Ray on the quality of a good MPG, I also love the Shuttle Pro 2 (not a fan of the express because of the size and button limitations).
It's nice because of the amount of buttons and dual wheels that make it attractive.
Just my 2 cents-
Dave
Dave,
My primary complaint with the Shuttle is the form-factor, which I found really inconvenient. It is intended to sit on a desktop, so is difficult to hold securely in your hand - pretty much takes two hands to operate even most of the buttons. As a result, I was constantly fumbling and dropping the thing. And it's really not at all drop-friendly. I lost count of how many times I had to crawl around under the machine to find those little clear key-caps after they popped off. Nor is it at all coolant- or chip-friendly. The MPG is also very low resolution, which seriously impacts functionality. The difference when using a real 100CPR MPG is wonderful - far more of a difference than I would've expected. I can do a rapid move of, say, exactly 137 steps in a split-second, without even looking at the DROs.
Believe it or not, I managed to put even more functionality into a VistaCNC pendant, using a simple macropump driver, than I had on the ShuttlePro I used initially. Any my newer Vista Pendant does even more. Neither has all the dedicated buttons of the ShuttlePro, though I found those to be sometimes problematic, as I would sometimes accidentally hit a button and do something unintentional. Nothing worse than bumping your pendant, and having the machine take off unexpectedly! I set mine up so every action requires either a double-click on a button, or holding the button while turning the MPG, so there's no chance of anything happening on the machine when you drop the pendant. And it can all be done one-handed.
Regards,
Ray L.