The latest gen Airsoft Innovations (AI) adaptor is extremely good. The nozzle tip is solid but has a little flex to it. It has not deformed one bit with heavy usage.
I had an early gen plastic one and the tip deformed after much usage. I also had a Madbull one...and while it worked well, it eventually jammed/stuck over and over and I couldn't get it working reliably again. I did use that one A LOT as well.
With the metal ones, I've bent/dropped/knocked my can over several times. One bent, one deformed the tip (I filed it back so it was flush again) and another was fine. Plastic ones don't suffer the same with knocks and oops.
Airsoftparts.ca is top notch...super fast on shipping.