i have the AFG2 and have had two vertical fore grips. the afg2 seems more natural its a happy medium of a fore grip and nothing. my vote is afg2 everytime
Looks aside, the vertical grip is a more versatile accessory. If you plan to do only standing off hand shooting and do target transitions the AFG is probably a good choice to try out.
The vertical grip takes up less space on the rail, so it can be used from the furthest forward to the furthest back position, and more easily in conjunction with another item on the bottom rail (light, bipod, etc). It can be used as a mini monopod on a table, bench, or sandbag and still allow your hand full use of the grip. You can still use the high thumb grip the AFG was designed for by gripping where the grip meets the rail. You can still use a traditional target stance without having to remove or work around the angled grip.
The AFG is slick, feels great in the hand, and looks pretty sweet, but it's not the be-all-end-all for forward grips.
In the end it's only a $20-30 investment though. Even if you get both there's a huge market for people wanting Magpul items-- you can likely sell the one you don't want and only be out a few bucks.
After much deliberation, I too selected none. I can always go back on my decision and put one on, but as of now, I just don't see how it will improve my relationship with my 15-22. Of course, I am but once voice among a million. And by the looks of the photos of guns with fore grips, a pretty quiet voice at that. I guess I would opt for the AFG if any at all. Enjoy whatever you decided on.
That's what I got for mine and EVERYONE who's held it completely loves it. I'd held others that were standard foregrips and it felt really weird. AFG feels so nice....and looks killer. And it's not so big that you can't put other stuff on that rail, especially with the AFG2 you've listed since it's smaller than the AFG1.