Yeah, probably very difficult to claim a best brand for any snow plow that will attach to a Grizzly as they all seem made pretty well based upon user feedback. I did first have a mid-mount but was having to remove the mount to go trail ride the bike. And although I agree the attachment points only hang down about 1" below the bike, it was enough for me to remove it to go trail ride. Those attachment points will get hung up in rocky areas and possibly bent or ??? That will entirely depend on type of terrain on the trails you ride. I instead ended up getting a front mount plow and do not need to remove the plow mount for trail riding.
I would just look for the best deal you can get on a plow. With the mid-mount plow, I had a 52" blade. When going to the front mount, I opted for a 60" blade. The Grizzly 700 can push a 60" blade, here in CO, with no problem other than you may need to have it in 4x4, have extra weight on the back or possibly use chains. I just use 4x4 to maintain traction.
One item I have read a fair amount of problems with is Warn's side-to-side plow actuator. It is an add-on product and seems pretty expensive for it to be having so many complaints. I've not personally used one to know for sure but based upon the constant complaints I've read, I would not buy one. Other than that, most seem to be very happy with their plow purchase, regardless of brand.