I thought this was the chain Serrano's, but instead it's a local chain within Arizona (I think).
We went with a large group of people, so that may taint my experience. The service was slow, and they missed one of our orders completely and ended up delivering it nearly 30 minutes after everyone else had their food.
We had some margaritas - overly sweet and completely forgettable.
We got the Del Mar sampler along with the steak fajitas. The fajitas were fine and filling. The Del Mar sampler came out two different ways. One of our companions got this (and it came out a startlingly half hour before mine did - they messed up in the kitchen) and it was blah. The fish was overcooked, and the other flavors blended into a mush. Mine came out later and the fish was done superbly - flaky soft with lots of flavor - and the rest of it was tasty.
I think there are better options within the Phoenix/Mesa area.