Man you are gonna be pissed when you misplace one of those. I had to purchase a set of used high angle open ends for AC work. Snap On was the only one that had that much of an angle. For standard box/open end wrenches I use Crapsman, I cant afford to fill my toolbox with the high end stuff.
Several brands make 4 way angle wrenches, and they all have the same 30/60 degree angles. Snap-On are the best in my opinion, but even the cheapest I've seen (the ones at Northern Tool) aren't half bad.
OP: That's a good deal at 275, and it'll continue being a good deal for a while longer. Those look to be in near mint condition, they're FD+, the set is as complete as it gets, and they're cheaper than the 400+ they'd cost you new. A bargain if that's what you're looking for -- I'm not looking for them, though, so for me personally they're too much.