any of things I've done online so far have been fine... although I haven't really played Mario Kart online yet.... but it will heavily depend on where you live, your internet connection strength, the number of players on the servers, etc. Honestly probably one of the WORST times would be the opening weekend as everyone with a Switch is hopping on.
In other news: I am doubtful Nintendo will actually do the paid online service. Seems counter intuitive as they don't have enough games that take advantage of online at the moment. If it comes ever I would not expect it this year. Because outside of Japan they're going to struggle to get people to pay for an online service (even if cheap) if all it is really being used for is Mario Kart and Splatoon
