Brass vs Plastic PEX B fittings

[NTM]

I am installing a shower using PEX B with copper crimp rings. I need to use a 90 degree elbows for my hot and cold PEX lines to reach the mixing valve without kinking them.

Should I use plastic or brass PEX fittings? Cost is not an issue, I'm just looking for the most reliable option because I will be closing up the wall and tiling.

 

[Reach4]

Both should be an unqualified reliable, but if we had a contest, go with brass unless you have acid water.. In the crimp/clamp fittings, brass has a higher ID too, tho a single normal showerhead would not be restricted by the difference.