I chose S Class based on their reviews here and elsewhere. They also have an instagram account where they show just about all their work so that you can see what they've done and it also helps to pick how dark you want to go.
I called Frank and was able to get an appointment for the next day for a great price. I originally wanted tinting in blue but he explained that the good tint manufacturers don't make colored tints and they can only be ordered from China. For that reason I went with the standard grey/black tint which they give a lifetime warranty for.
His brother ended up doing the tinting for me. S Class operates out of another body shop which was very professional; perhaps this is partially how they can keep prices so low.
I was able to get it all done in less than 2 hours which was great. They appear to have tinting available in 5% increments and so I got 5% tinting in the back and 20% on the sides.
I'd highly recommend S Class for their product knowledge, price, and customer service and may very well be back soon to tint my windshield!