Single player is worth maybe $20? It feels kind of empty and unfinished, or rushed? Still fun but not worth the full price.

Thought I'd give online a try. It's full of griefers, squeakers, and modders. Met at least 3 modders in 4 days of playing. They screwed me over royal and I ended up in the bad sport lobby for two days. Do you have any idea what a hellscape that place is? Never did get any compensation from rockstar, even though I filed multiple tickets.

I guess the online races are fun, but good luck finding players who aren't there for a demo derby or else quit when you take the lead.

TL;DR
Single is worth $20 maybe. GTA Online is a broken mess that Rockstar has no incentive to fix.