On Monday, March 11, 2013 10:57:19 PM UTC-4, Ed Pawlowski wrote:
I never heard of them until a couple of years ago on this newsgroup. Fantastic, they are. When my house was build, the baseboard heating tubing had to take a bend at the shower stall. The plumber put in a bellows type of flex unit and after a few years it started to leak. I replaced it and it was a PITA because of the location, difficult to sweat the joints. A few years later, it leaked again. This time, I drilled a hole in the base of the shower enclosure and ran a length of PEX to the other side, connecting under the stairs of a split entry stair. Very low head space. Again, all was well for a few years and the couplings leaked. Tightened them and all was well or another year. This time the drip would not stop. I bought a couple of Sharkbite couplings for 3/4" tubing. Cut a new length of PEX as it had to be slightly longer. In the bathroom, it was just snap/snap, then crawled through the closet and under the stairs, snap/snap and I was done. Wish I knew about these 20 years ago when all the trouble started. While they are much more expensive than regular couplings, they have a place where they save a lot of time and trouble.

I used a few for a transition from cpvc to pex and they are pretty handy. The price prohibits me from using them unless the situation really calls for it. I can see how may homeowners would choose them for copper as you need to know what you are doing to sweat copper and you have to get all the water out.