Unless you’re spending a LOT for a hinged model, they’re really all the same. I personally prefer brass deflectors which kick brass straight down instead of catcher bags, but bags work, until they don’t, and access to clear malfunctions is limited.

The slip on picatinny mount type is generally easier to move out of the way to clear malfunctions (remove), but they’re foolishly designed, since the vast majority of MSR’s have optics, saddled in 1pc mounts which cover the entire pic rail above the port.

So personally, I use clip on deflectors far, far more often than bags.