I've got a 2R non-mips.
I chose the non-mips version, in part because the plastic mips liner was enough to create two pressure points on my head. I would be interested to see any actual independent research indicating effectiveness of MIPS system. seems unproven, and people buy it because it MIGHT help, rather than actually.
If you think it will help, and fits your head ok, by all means, buy a MIPS version. makes no difference to me.
Any decent helmet done up snugly but not too tight to breathe will have some degree of lateral movement, a good 5mm or more in any direction.
From my own reading on helmets, any helmet with a fairly smooth outer profile and no significant fins or other protrusions will (theoretically at least) be beneficial in a crash, as the helmet should be more able to slide on rock or dirt, rather than dig in - with potential forces resulting from that.
Bell Super 2R is good in that regard as it has that profile. as long as you don't mount a camera on it. it does come with a gopro mount which I believe is break-away, but not 100% on that.
Visor is fairly flexible and seems as though it would snap off nicely in a crash, rather than act as a force multiplier.
Ventilation and comfort has been pretty good, especially for an AM helmet with decent head coverage.
I have fafffed around with the strap system a bit to find a balance of snug fit, retention on the head, and easy breathing.
I get the impression that the helmet retention relies a bit more on the click wheel at the base of your skull at the back, and the cheek pads on the removable chin bar get in the way of the chin straps. The cheek pads are fairly soft and squishy, so it may not be a major thing, but you may find yourself adjusting the straps a tad when the chin bar is on.
No offs where my head smacked the ground. The chin bar has a fair degree of flex laterally, and a bit frontally. Not rated for DH. Varying reports on its protection effectiveness, but better than headbutting the ground with your face. make sure the damn thing is latched properly, or it will be worse than useless.
I've ridden with the chin bar fitted at Youies (non-DH tracks) and a DJ session. Vision is good, IMO. Worn with sunnies but not goggles. Chinbar ventilation is very good.
As always, you will need to try it on as it may or may not suit your head shape.