I can't speak from experience on the Vaughn-manufactured Grafs about holding up over time as I just bought these, but I do know Vaughn's products are respected, and an inspection of my 7900s gives me the impression these are as well made as my 10+ year old Grafs, or anyone else's product currently in the marketplace.
I plan to skate on these a few more times to get comfortable, and possibly buy another identical pairs as I normally rotate my gear, and usually bring 2 pairs of skates to the rink as I block a ton of shots and have broken blades before.
Rotating skates, especially once I start playing a few times a week again (hopefully, pandemic permitting) helps keep them "fresh" and able to last for hopefully 10 years, which I've heard is a lot longer than most people keep their skates.
Given that some of the past 10 years I was on the ice 4-5x per week, I'd have to say I got my money's worth with my G70s. I hope to do the same with the new 7900s.