I've had two tanks built so far by different builders, and while both were fantastic, SoCal far exceeded my expectations.
Throughout the process they send you updates, pictures, and in the planning process they are very helpful.
I find that with some builders, you have to mention every detail or else they don't do it. With SoCal they will do everything you say, help you make decisions, and make it even better.
My first tank was a 82g which is now in posession of GorillaReefer (I think a MARS member), was simply a 32"x24"x24" tank, eurobraced, with an external overflow with a few holes drilled. SoCal went ahead and made the front corners polished rounded, the top edge polished and rounded, they also made the eurobracing such that I had a lot more clearance than I expected, and precisely drilled holes for a closed loop etc. Amazing work! My other tank, a 98 gallon, 36"x25"x25" was also made with the same specs, but i failed to mention to polish the top eurobracing and round it, and alas, it was not touched by the other builder. My fault, but you can see how SoCal goes above and beyond. SoCal also never skimps on safety, durability, and quality. They use one of the best acrylics, Spartech Polycast, even though it's much more expensive. It was almost impossible to get my other builder to use this acrylic, even willing to pay a bit more, just because they couldn't charge that much for everyone with the left over pieces.
Randy/Steve at socal are great! They will make your tank redundantly strong, and it will definately look great.
They also do amazing work with their stands and sumps. I'd recommend getting the whole system from them, since they make stands to spec and aren't expensive. Sumps are also made just for the tank, to fit perfectly in the stand, so no guesswork needed.
Fantastic work =) I'd highly recommend them.
(their shipping is very reasonable too, and the way they ship is they make a crate for your tank. the crate is amazingly well built too, haha!)