Actually, the AMBASSADOR card is barely distinguishable from the regular PRIORITY CLUB card. You will receive a single "combined" PC/AMBASSADOR card. The "basic" AMBASSADOR version of the PC card will be blue on the left side, gold on the right to signify the PC GOLD status. It will still say PRIORITY CLUB in bold letters across the top of the full card, and only be different from standard PC cards by having an IC logo and the word AMBASSADOR in the lower right corner, just over the expiry date.

So not sure if it will do anything more than your old card when using Priceline and similar 3rd Party bookings. But you are right that just a single stay at a "real" IC will make the investment worthwhile, particularly if you can use the 2nd Weekend night certificate.

While I haven't registered for the promo -- I have pretty much let my SKYMILES account lapse once I moved out of a major DL area a few years ago; used to be top tier WESTERN AIRLINES and then became MEDALLION when DL took WA over and continued for many years when I lived in the west -- I did register a colleague who I was going to register in PC as he often stays at HIs in Africa. He also had 76K in his SKYMILES account, so this was a great deal to top up his SM account [US$150 now gets him a J seat just about anywhere from NAmerica to Europe and Asia when he decides to cash in his miles] take advantage of PC and get GOLD status from the start.