I've replaced a lot of my system with PEX. I totally re-did the area where the pump
and water heater
are. I haven't replaced the lines to remote
fixtures; so far they work
I went with "shark bite" (or similar brand) press-on connectors and fittings, on the theory that they're easy to remove and re-install without tools. For some reason I seem to need to do this more often on a boat than I ever did on my house.
That said, these fittings are more expensive, and removing them isn't always as simple as you'd think, if they're in a tight location or there's not much room between fittings.
For the house, I bought the PEX ring compressor
tool for a small job, and I'm liking this method a lot. Easy one-handed install, and removal
isn't too hard; just replace that section of PEX. It's cheap
enough not to bother re-using the old section.
If I had it to do over, I'd use the shark bite connectors where I thought I might need to someday pull the connection apart, and the compression
rings on the rest. The tool isn't that expensive, and probably cheaper than buying
all those shark bite fittings.