Best underfloor heating pipe?

Hi All,
I'm in the process of a new build, and have been reading alot about underfloor heating on these boards.
I have a plumber ready to lay the underfloor heating pipes, but am unsure as to what pipe to order
My options are basically the pipe that contains a metal layer as the O2 barrier i.e. unipipe, pex-al etc. or a plastic pipe (which still somehow contains an O2 barrier) i.e pex pipe
I dont mind which supplier I use as long as the pipe itself is the best for the job! My plumber thinks both types of pipe are good.
The question basically is : pipe with or without metal layer?
Please help

Have a plumber here right now..

He says definitely to use any pipe with the metal barrier. Can be a bit more awkward for your plumber to work with but a much better end result.

+1 on the metal lining. I used Unipipes pipe.

Thanks,
I needed to make sure there were no performance issues with the pipes + metal lining. Just have to decide now between unipipe and pex-al. Oh the joy.....