Honestly, some of us really do not need to test it to know it is a deal killer. Even if it works spectacularly in Photoshop, which I doubt given the sloppiness and laziness of Adobe in coding over the past few years, there are other business applications out there which are now mainstream (and very expensive) that know of no existence beyond Wacom. Drafting and GIS applications come to mind first. This may be the best pen the world has ever seen and use of a proprietary design still makes it a niche product that I can't sell to the tech people in my profession. More to the point it makes it a product that, if I can use it at all, will involve compromises in workflow.
Sorry but this isn't idle speculation, it is simply a fact of life regarding where the markets are and how fast (and for what reasons) they advance change. Surface Pro 3 would need to be an original IPad level runaway success to see bona fide adoption in some pen/digitizer reliant applications within a year. Even at that, in an era of cost savings and lean development budgets, these companies need to design for Wacom digitizer technology for existing hardware that won't be updated for many to Windows 7 for another year and Apple products still justifiably loved by many graphics/design people. For me Microsoft has designed an otherwise exceptional product, although I still like the smaller form factor, but then threw in something that hamstrings it. There are reasons they went with a Wacom pen with Surface Pro and Surface Pro 2 and nothing has happened to change that particular technological landscape. It really may be a wonderful device and a great pen but on the digitizer front, I cannot justify Surface Pro 3. It would be Surface Pro 4 or 5 before it could even be in the cards. If there was one thing they should not shift fro industry standard, this was absolutely it.