They’re both good, I’m using both on various bikes… Never had any bother at all with losing pins in 2 years of using MGs and they’ve taken some pretty horrible knocks, I wouldn’t have blamed them at all if they’d shed a couple. Cage is a wee bit out of shape but nothing to cause a problem. But I do reckon the Nanos are more durable.
Grip, mmm. Well is it that simple? I reckon that the MG1s have more outright grip despite the smaller platforms, the pins seem to be better located for me. But, the thinner body of the Nanos seems to mean that when you turn the pace up a bit they don’t need as much mechanical grip, to get a better result. Both have far more grip than they need even before you stick a sticky shoe on them though.
I like both. I’ve ended up with the Nanos on the bikes that get the hardest use and the Nanos on the lightest most XC bike but honestly I would be totally happy with any mix or combination, they’re both very good.