I've eaten at Senor Flaco's a couple of times and liked it enough to go back. The best for me was to go for drinks and appetizers as their menu isn't so big. The nachos are loaded and they could be a meal in themselves.
On Sundays, kids eat free with the purchase of an adult entrée. we took the kids for that reason and ended up glad it was free because the kids menu was quite bare and most of what was ordered ended up wasted.
The portions are decent sized and the prices aren't bad. The food is okay, it's just nice for a change to have a mexican food place in town.