Every game in online history has had issues. Some more than others. A game with this much involved, I can only imagine the coding their developers have to go through to tinker with. This is the first type of console game where it's like this; 10 saved cars, apartments, activities you can do with people in a lobby, crews, etc etc.
And btw; you can't really compare SAMP on the PC to a console game. GTA Online will probably be much better on the PC and less flawless. Sure, they've had time to work a lot of it out, but it's much easier to fix and patch a PC game than it is a console one.