Alloy,
Yes, I have that exact 4 axis DRO on my Birmingham mill. It's all Tpack says it is and has performed flawlessly. Like any other DRO you're going to have to fab some of your own brackets as well as the chip shield for the Z, but not a biggie really. My machinist buddy laughs at me but I really dig the calculator function. I use it ALL THE TIME! It has all the bells and whistles of the high dollar units and in the hands of a capable operator (not so much me yet) it will do it all. I've mic'd and measured by digital calipers and the numbers are spot on. I believe that coincides with attention to detail on initial installation.
I can highly recommend this product and supplier by personal experience.
Almost forgot; when I first purchased my unit the "K" scale and reader was on backorder and wasn't expected for several months. I didn't throw a hissy or anything and a few days later, it shows up, he'd gotten it from a competitor (different brand markings, same thing) in order to take care of me. After he'd credited me for having not received it. When he saw it had been signed for, he rebilled.
Could not be more pleased.
Hope that helps.