I don't know anything about Dr. Umbach, but I did have my sleeve surgery on October 8, 2009, by Dr Francis Teng. He is a general surgeon, however, he has been doing the sleeve surgery for the last 7 years. In my research I have found many people who have used him for many different types of surgery (including my dentist) and everyone said the same thing - he runs a tight ship, has used the same surgical team for the last 7 yrs here in Las Vegas, including his brother who is the anesthesiologist. I was a self pay and once I made the decision to go thru with the surgery I had the usual tests plus he required an echo since I previously used phen/phen . It wasn't realistic for me to travel to Mexico as I am the caretaker for my father - the cost of hiring a caretaker for at least a week, the travel, just the fear of being in another country for surgery and possible complications - it was worth it to me to stay in my own town - hospital 10 minutes from my house - an overnight stay in the hospital - wasn't cheap (25k) but Dr Teng's office follows you for 2 years and the hospital (Mountain View) follows you for 5 years - no follow-up charges by either. I figured if it extened my life a minimum of 25 years - that's a thousand dollars a year - less than 1 hundred dollars a month - I felt I was worth it. Good luck to you on your surgery with whatever doctor you select. It was the best decision I ever made. Renee