I am originally from Europe and you do see a lot of PVC gutters in my country, especially in construction that is done on a tight budget. It seems to me PVC would be a legit material to make cheap and durable gutters. How come you don't get to see (m)any here in the States?
If you use PVC gutter stock, it needs to be solvent welded at all the joints. Don't bother with any of the clip-together DIY grade junk that's out there. Having tried two different manufacturers, here's the basic results on the clip-together stuff:
Vinyl's high expansion rate means that it grows mightily when hot and then contracts in cold weather, straining all the joints. No matter now much movement the brackets are made to allow, they allow ratcheting during summer heat, causing the gutter system to pull itself apart when cold weather hits. if you are using the common DIY clip-together stuff. Nothing makes you so angry as being on top a slippery 15ft. ladder in a typical winter Oregon downpour with the full gutter flow shooting out the gap, through your collar and down inside your raincoat. Various neighbors around here have tried it, cursed and thrown it away. If you're going to install it, the first hint of fall should be followed by a full inspection which means pulling the gutter stock back through the brackets so they fully seat in the connection and downspout joints.
Solvent welded vinyl gutter still has the same expansion rates, hopefully the support systems take that into account, I didn't bother wasting any more money on vinyl, but went with continuous construction aluminum gutters.
With continuous aluminum, you have no joints, it's one single run from gable to gable, the finish is baked on and it's held up over the 5 years it has been in operation much better than vinyl and hasn't got the rust problems that galvanized sheet iron has. It has been worth the money spent on it.
I installed solvent pvc gutters 30 years ago on my home on the New Jersey Coast. I am only 700' from the Atlantic Ocean and 300' from the bay. I have never had any issues with it except for green moss on the outside every five years or so on the North side which washes right off with a garden hose. The big plus here is it will not pit in the salt air and it has held firm during high coastal winds. It still looks so good I don't anticipate replacing it anytime soon......maybe another 30 years!