After jumping in feet first only to find a number of "issues" I'm definitely ambivalent.
I've got a bunch of old images (jpg's mostly) that I had converted to NEF's in Capture. Media Pro (and Capture One) will not access those images. As the manufacturer rendering has been removed and there is no 64 bit WIC codec from Nikon, those images were no longer rendered on my Win7 64 bit machine. A quick alert to Phase One support acknowledged the issue with a bit of a "tough luck" remark
I was able to procure a third party WIC codec that provides that function and now I my NEF's are rendered.
The level of interaction of Phase One personnel in their forum is frankly a bit disappointing. Occasionally someone named Drew will chime in that "they are aware of the problem" but that's about all. I was hoping PO would see the forum as a tool to help them manage the product (ala Hert and IdImager), but alas that seems not to be the case.
About the only thing I'm certain of at this point is PO will see no more of my hard earned money without a thorough and detailed evaluation of any future "upgrades".