Decent watch, could watch again, and can recommend.
It definitely doesn't stand alone, you've got to see the first movie for this one to have enough context for the situation.
It is nice that they shuffled the structure around a little, giving Kumar the love interest instead of Harold, but he's still the "problem causer" in the pair. This turns into more abuse humor focused on Harold, even more than the first movie.
Where the first movie had a much more passive antagonist and it was more of situational adversity, this has the U.S. Government as an active antagonist. This makes it political and a little less fun, but more importantly it about them running FROM something as opposed to running TO something.
While this formula is a little less fun by structure, they managed to up the ridiculousness of the situations from the first movie. I honestly think they just did everything they thought they couldn't get away with in the original.
I can easily say this is just as good as the original, which feels rare in movies.