Yeah, my experience with lag and DC has been fairly minimal save for a couple moments of DC/Lag that was hitting everyone at once. I've prob put 60+ hours into this (im really disgusted in myelf!).
Like I said though, I have a friend that is local and has put in similar hours, and he gets a lot more DC/lag. I've played games with Japanese players, but haven't had any matches with them that caused lag.
Matchmaking just seems wildly inconsistent from each player to the next.
That does appear to be the case; I have coworkers in Midwest USA who have frequent lag and DCs, but local friends who have had better luck. I am sure Nintendo will be upgrading their infrastructure in the coming months, especially ahead of the major update in August. Overall though, I am very happy with how this turned out with their first foray into online shooters.