In my area alot of the homes were built in the 70s and 80s. Copper was the choice plumbing material here regardless of water pH. I grew up in the area and my Dad built our home with copper pipes. I have no clue what new construction out here is using but from my visits to Lowes and homedepot its clear the copperpipes and fittings section is getting smaller whereas Pex is growing.
Just the installation benefit of PEX.. anyone can install this stuff. Its cheap, It cuts easy, is flexible to a greater degree, and fittings use simple compression bands, greater resistence to bursting from freezing. Repairs easy even if theres some water in the pipes.
Copper is harder to.work with, takes some practice to install. Sweating fittings can be challenging if theres any water in the pipes. Torches are needed..its very expensive... so expensive that in my area theres been a problem with people breaking into new homes or unoccupied homes and ripping out the copper pipes for scrap $$$. Acidic water DOES eat it away. All my life I have always had a copper pipe repair kit.. a few lengths of pipe,various fittings, torch and solder..everything I could use in a repair at 2 am in the morning. More recently I have added sharkbite fittings to my kit.. what a life saver these are!