If local code allows; anybody know?
Just a quick google search turned up results of Houstonians installing PEX without issue.
I won't EVER install copper again unless it was exposed to sunlight. I could run all the water lines in my house in a day with PEX and be done by noon AND it can freeze solid and not burst. Where I live, that's a big plus. We've had the PEX under our kitchen(exposed) freeze several times every winter and it's still working just fine. Every other year I would crawl under there and fix the frickin copper. The PEX has been maintenance free for 8 years now.