Redoing shower - PEX and new valve?
I'm almost finished demo of a 36x36 shower with an acrylic pan. A contractor who came by for a tile estimate said I might as well update the valve to a thermostatic (current one is from 1999). I did not know the valve was specific to the trim, so in order to update the valve I must now choose a trim before I can put the tile backer board on. So now the project is stalled until I find a trim I like at a price I like.
First question is given the price differential of let's say $150 to $400, am I just paying for a better looking trim or a better quality valve too? For simplicity, let's assume both are the same brand. Frankly, I don't see myself paying $400 for a knob, escutcheon, shower head and valve unless the valve is 2x better (however "better" is defined) and material/finish is night and day compared to the $150 set.
Second question is I was considering putting in a shutoff valve for each supply line then using PEX for the remainder plumbing. Any opinions about using PEX? Ease is my main motivation, I've never sweated copper pipes. I've read installed properly, PEX is reliable, but the fact that hose clamps fail all the time in cars doesn't give me high confidence that PEX crimp will last indefinitely. I understand operating conditions are different, but still, it's a crimp under pressure.
I know I'm hard to please, but I'm more of a function over form kind of person so paying a huge premium for looks makes little sense to me personally, but I don't want a new shower to look cheap either.