I would ask anyone local who advertises they do Shiatsu:
1. Where did they get their training?
2. How many hours do they have?
3. Is it floor or table work?
4. Can they describe their technique?
Look for someone who has plenty of training. They should know their meridians & eastern techniques as well as you know your muscles & western techniques. Look for someone who does floor work & incorporates meridian reading, acupressure & stretching in combination. If you can get a referral from someone who recommends them - even better. You'll want to wear loose-fitting clothing & don't eat a lot before your appointment. Drink lots of water after! (Like regular massage).
I love the Ohashi style of Shiatsu. Don't know where in Florida you're located, but here's someone in Boynton Beach:
http://www.wilburmay.com/ohashi.htm
He teaches, which means his skill level is high, but I notice he's also available for individual sessions.
Here's someone in Ft. Lauderdale:
http://www.ohashiatsu.org/Bios/US/GwynethCatlin.html
I love shiatsu. If you follow through on an appointment, let us know how it goes!