Hotwire is weird. I spent a lot of time on it playing with dates to try and find a good rate at a Universal hotel, but none of the three were showing up on Hotwire for my dates. Now the PBH is showing up for my dates -- a few days ago it was $155 and now it seems to have jumped up to $177. I guess the trick is to jump on a low rate when you see it -- but there is that darn non-refundable issue.
Also, I'm not sure but I think that the Hotwire dates and rates track the Entertainment Card dates and rates pretty closely -- at least, that's what was happening for the various dates that I was checking (if an Entertainment Card rate was available, the same rate would show up on Hotwire for the same date). So if you have a choice, it makes sense to go with the Entertainment Card rate, since that reservation can be cancelled; also, I think that Hotwire charges a (relatively small) booking fee.