That's why we use polysure; fittings not cheap, however they are secure
Doesn't Polysure still rely on rubber O-rings to seal though?
I've used a lot of Rehau PEX with there everloc fittings over the last 3 years or so for new builds and prefer that, no grab rings and no rubber O-rings to deteriorate, pipes flared and then a brass sleeve is pulled on to the barbed brass fittings with a machine. I'd imagine its atleast twice as expensive as polysure though.
I would be tempted to look at Buteline if I wanted a cheaper alternative, as again theres no grab rings and no O-rings, the PB pipe is just slid into the barbed fittings and crimped on with there crimp tool which is only £30 or something. Hugely popular in NZ but a few places stock it here now.