I played with the Genesis RSST for a while and put it on the back shelf for future use. I didn't like messing with mesh that much. I ordered the air flow cap, but haven't tried it.
I got sidetracked on the EHPro
kayfun 3.1 and haven't put it down. I've done lung hits with the Kayfun and it does them well, but it's not a free flow air system as some like. It's more like the Protank/Aerotank family with adjustable air flow. I'm not a lung hit fan, though.