It is really good, and I definitely wouldn't have thought of it either. When I ordered it, I thought I was taking a big gamble.
When I make it at home, I usually make a larger batch and eat it for a couple meal/snacks. It's good for at least a couple days (I wouldn't push that much, though being seafood), and while the flavor improves the longer it sits, the texture of the shrimp get's firmer and chewier as the acid in the sauce further "cooks" the shrimp.
(By the way, for Weight Watchers, the WW points on the whole recipe without the avocado is 4 points. 3 points for the shrimp, and 1 for the Picante sauce. I think 1/2 cup of Picante sauce is free, so you can reduce the Picante sauce, if you're in a point crunch).