Table side guac is such an awesomely good idea. They'll make it here as spicy as you want, even throwing in habanero peppers if you think you can handle it. Besides the appetizers I tried the mahi tacos and they were great, baja style, but very, very lightly breaded and fried. We also had the please of trying mini-churros with a milkshake (mmmmmmm), fried bananas, and bread pudding. I'm not a fan of bananas or bread pudding so I'm not a good judge of if they were good or not, but the rest of my table assured me they were.
I also really dig the interior of The Mission. It sort of reminds me of the Alamo, although I only ever went to The Alamo once many years ago so my memories could be wrong. However, it has that open, cool, stone feel with tons of great chandeliers and candles hanging around and setting the mood. So, um, check it out and get into the mood.