After what I read on the Airstream forums, I'm leery about Sharkbite fittings because you are one O-ring away from a major leak... and if it isn't nicked by inserting the pipe, eventually chlorine, vibration, expansion/contraction cycles, and other items will wear away that O-ring. I'd be more confident about Sharkbites/Probites/etc. in static installations, while when on the move, I'd like something standing between the water inside the pipe and certain doom than just a single piece of rubber.
On the other hand, Sharkbite has a 25 year guarantee on their fittings, and that says a lot.
What I read that a lot of people used would be Flair-It fittings. they don't rely on a single O-ring, but when tightened down by hand, put pressure all the way around the PEX pipe. Tighten them until they start to squeak, then turn another half turn, is what I read the best way to ensure they are cinched down properly. They also assemble and disassemble without tools. Downside is that these fittings only have a 2-5 year warranty.
