I've been a few times and like them well enough. The food is really good, and it's a cool place. I haven't had any of these nitro-cans (they're new tech - no widget), but have heard good things. Wish I could make it there Sunday, but I'm busy. Had an ESB on Nitro at the New Hope Beer Fest that was pretty tasty. Here's a recent-ish thread with mixed opinions, but the opinions have been getting better: http://www.beeradvocate.com/community/threads/vault-brewing-yardley.205988/
I believe the last batch of Nitro Cans lasted until they released the "Apple Brandy Barrel Aged Russian Imperial Stout." In which case, that along with any remaining cans vanished. Nonetheless, I expect this to last a bit, but could be very wrong, seeing as though this is the first Nitro canning of the Rye
This is correct. They lasted for about 2 weeks (although they said they held back a certain amount of cases for the RIS release). The first release sold out within 2 days, which a couple of cases being sold a weekend or two afterwards. I would say that these should last about a week or more as their Rye Pale Ale isn't as popular as their Coffee Stouts.