You know that expression: "less than the sum of its parts"? I feel this applies directly to BB. All the ingredients seem present and fresh, but there's just not a terrific result when it actually comes to the eating.
One key indicator for anything wrapped (burrito, Shawarma, etc...) is the quality and seasoning of the meat. In this case, the 'steak' is very mediocre in quality, not very tender or memorably seasoned. Same could be said about the chicken.
I like that they include guac in it, but that said - it isn't that great either. Even Bar Burrito 5 mins up the road is better, but probably don't do in a day what BB may get in an hour.
Certainly not poor, but a pretty definitive '3' if there ever was one.