Looking at the specs for both the Foray and the GR2, it looks like these shoes are virtually identical. The only difference I can tell is the binding of each shoe. The Foray uses a single boa along with a velcro strap at the toe. The GR2 uses laces only in place of the boa and strap.
In fact, if you look at the profile of each shoe along with the sole, you can tell they're pretty much the same shoe:
Same damn shoe, right? They basically just took the Foray, updated it with laces, and threw the "gravel" name on it.
Still, at least Bontrager is giving people choices. I just wish they didn't capitalize on the use of the term "gravel" just so they can put a product out there with the term as part of the name.
Reading reviews of the Foray's should give you an idea of how well these shoes perform. If you've worn Bontrager shoes before you know what to expect: they're not too narrow or too wide. There's a bit of room in the toe which, for me, is preferred.
Like many other reviews have said, these aren't the stiffest shoes available but, for the money, they offer a lot of bang for the buck. The default insoles aren't anything to scream about but can be easily replaced with better ones. I purchased a set of Specialized insoles to help add more arch support.
Aside from that, I can tell you that I've been pretty darn happy with my Foray's. I honestly prefer the Boa binding over laces. So, if prefer a Boa over laces then I would recommend paying the extra $10 and getting the Foray's. However, if you really like laces better then go with the GR2's.