Little softer shooting, potentially & directionally less reliability, but I've never seen it.
With rifle gas, you can usually use a carbine (3.0 oz) buffer, with mid-gas, unless you are using an adjustable gas block, you will likely end up with a H1 buffer, IME.
I have both mid & rifle gas WOA, 18" barrels, & as set up with adjustable gas blocks, I really cannot tell much difference in their shooting.
If you're doing much shooting in pretty cold weather, the mid-gas is potentially more reliable.
One other advantage if rifle gas is that due to the lower port pressure, you will seen a slower erosion of the gas port in the barrel.
MM
