JP components offer tunability that cant be denied, however, ARs are tunable in more areas than just the gas block. I run a brake & enidine buffer with my Adams Arms piston gun. Of the 3 AA systems I use, all are equiped with FF tubes. I ran 5,000+ rds through my main AA gun last year. I shot that paritcular gun in several matches to include the ITRC. Notably, in the gully course the gun did not get too hot to hold onto, which can be a problem (it seems like that course used 15ish(?)30rd magazines). I had exactly 4 malfs & i'll tell you why- I was trying a Hi-Power trick of putting grease in my buffer tube, turns out you can put too much in. I dont feel like there are any notable disadvantages but I can only speak for the Adams Arms piston system in particular.