In my opinion the best dry suit for you is a highly personal series of choices. I would say that first and foremost the fit is key.
Fit is extremely important, also, consider the quality of construction, type of material the suit is made of, design features, optional features you might add, and customer service in case of problems.
For me since I am almost an exact Extra Large for a stock DUI suit I have a stock CLx450. In my case the suit has been modified from the basic with pockets on both thighs, ZipSeals on both wrists and the neck, knee pads, also the older CLx series suits are just a little different fit than the TLS350 for example, and this slight difference in the fit of the suit works in my favor. The CLx size XL actually fits better than a TLS size XL. The difference is minor, but noticable.
You will be different so the best suit for you will most likely be somthing different. Try suits on, and rent if possible. Look at lots of different brands. Pick the fabric and look at lots of options and choose. For your first suit you might consider eBay if you want to save some money, but be warned a used suit may cost almost as much a new suit by the time you replace seals and fix leaks, shop wisely and lookout for fraud.
Best of luck,
Mark Vlahos