I think the argument against plastic is growing.
I see so many problems with it.
I detest that there are different brands of plastic pipe, each requiring their own make of pipe support.
I also hate the fact that plastic plumbing requires a high pressure test to make the grab rings bite (few ever bother doing this anyhow).
When plastic plumbing didn't exist there wasn't so many homes getting flood damage, due to fittings coming off.
Plastic plumbing is not cheap, although it can make some labour cheaper.
Compression joints on plastic damage the pipe where the olive bites.
Copper is more self supporting and plastic pipe is never straight.
Rodents eat the fittings and the pipe.
UV rays damage all plastic.
If a heating system overheats - the plastic will melt.
Disadvantages of copper are mainly it can corrode in certain water areas and soldering is a fire risk. Installing copper is normally no bother to a decent plumber, but can be slow and difficult to install long lengths of copper below floors etc.
Remember that many plumbers install copper and plastic, but nearly all cowboys use plastic.