Do they stop all that banging about on the chainstays? is there any other advantage or disadvantage?

I dont get any banging from my XT shadow the other benefits are:
less chance of a rock interface
better cable routing
better jockey wheels than SRAM equilivant

Yes you still get chainslap – I was never aware that they should stop it.

Although only an inch or so more inboard than regular mechs, its an inch that does actually make a difference.

Also easier to adjust H / L screws as you can see the stops

Pieface I thought the OP was about the ‘knuckle’ on older mechs that used to hit the underside of the chainstay. Not chainslap which is pretty hard to avoid.

Heasay says that they are weaker

What do THEY know about bikes???

I have broken two of them at the pivot. Both times they took the hanger with them, but the cage and body were fine. I rckon if i had a regular one the hanger would still have bent but the mech might have been OK. Maybe…

Yep it was the mech banging about on the frame I wouldnt mind losing, thinking of a new mech and wonder if these are the way forward.

mech still bangs on the frame with SLX shadow