It's really crowded most nights, from 6:30 or 7:00 on, and Thursday would certainly be no exception. I do find parking to be consistently not awful, leaving you with at most a five minute walk (although now I live within walking distance).
For Southern Mexican cuisine, Angela's Cafe in East Boston has stolen my heart, but the food at Tu y Yo is still reasonably tasty, and the liquor license certainly doesn't hurt.
I haven't been there in at least a year, so keep that in mind:
I have never had to wait for a table there. The only parking available is off street parking, which can be difficult. We typical have to circle around a few times before we find something. It's a weird spot that is largely residential except for the small group of storefronts that includes the restaurant.
I really need to go back. Their food is great and authentic. The first time I had huitlacoche was there. Yum.