When JPop sold some P-ROC and other PDB boards of Gerry's on the other forum, I'm the one who bought them. I can assure you that they work just fine.
What can't be done with the p-roc+PDB boards? We have seen lots of alpha numeric, dmd, and full-color games out there built on the platform. I'd say a pretty good number of games have been made and some (admittedly few) have been sold, but I'd include CCC and BoP2 in the list of titles that prove the P-roc as tried and true.
Since we know there's no technical hardware limitations that really justify not using a p-roc based boardset (and it would be dubious at best for anyone to imply otherwise), the reason not to go with PinballControllers has to be either financial, political, personal, personnel (ie, no one to code in Python (pyprocgame), C++ (libpinproc) or C# (netprocgame)), or some combination of these factors. Since you guys are talking about using MPF, seems a lack of available developers was clearly a factor.
I read Eric's post as: there absolutely is more of a story here, and some of us wish we knew it. You can sure add me to the curious list!
Quoted from fastpinball:
My point was that John has looked at all options and is continuing to do so. If he wanted to use proc he could have years ago.
But you seem to have insight on this decision and can probably speak to it better than I.