my 2p worth
had a max flow on my lcd, worked flawlessly cant fault except it was as attractive as jade from big brother, new one sorts that. mount was a bit toss tho, brings the bottle very close to the base of the grip making it tight on big hands needed a drop which made this system v big
now have an angel air, added bling and techo jiggery, easier to adjust, but if your batteries die you'll wish you had normal gauges. many smart mounting options available. no on/off tap so you'll have to add one.
i'd have the new max flow for pure performance and reliability, if you want a bit more of an ooooooh factor to your rig, get the air