It is just out of the way, I think. Unless you're staying at CSR there's not much reason to go there, and even then a lot of vacationers prefer evenings in the parks.
We ate there on our trip last month and I really enjoyed it. Like any good Mexican restaurant, they start you out with chips and salsa rather than bread. The chips are good, nice and light, and the salsa has a good flavor without being too hot for the kids. My kids (DD and her BFF) are both too old for the kids' menu but our waiter happily made them up an adult-sized version of the kids' beef tacos when they found the complexity of the descriptions on the adult menu a bit daunting. I ordered an enchilada sampler that was quite enjoyable - the chicken enchilada was a hit all around and I ended up sharing it with both girls. They let me have the pork one to myself because neither liked the sauce it was served with (salsa verde IIRC). The beef was the weakest of the trio and for the same reason the tacos weren't a huge hit with the girls, something about the way the meat was seasoned didn't suit either of them. I enjoyed them, though, and ate their tacos as leftovers the next day. We wrapped up the meal by sharing fried ice cream, which wasn't the best I've ever had but still good.
My favorite part of the meal was the entertainment, though. They had a guitarist that played a really amusing variety of songs in an acoustic flamenco style, everything from the Beatles to Jimmy Buffet to Guns & Roses. At Disney, where the norm is loud restaurants and the background din of scores of kids, it was a wonderful change of pace to be in a less-than-packed restaurant (we walked up around 8pm, it was probably 75% full) with a quieter ambiance and relaxing dinner music.
I'm actually hoping to make time to pop in there for dinner or drinks when I'm back solo next week, but there are so many things to do and so little time that I'm not sure I'll make it.