See if you can find a Malibu Pro Xplorer. If you are a tall guy, like over 6'2", you really need something like a Malibu XFactor. It is a great big guy yak.
It is a bit heavy and you will hear it is slow, but you will have a dry ride, which is important to me. Always consider the "dry ride" as a big thing. A yak may be faster than another, but if your butt is sitting in a couple of inches of water all day, gets really aggravating.
You will find all different answers, but I have owned Wilderness and Hobie yaks, and the Malibu X Factor or Malibu Pro Xplorer are the two driest rides I have found.
Also important is getting a good seat. You will spend lots of time in it, so you need to get one that is comfortable and gives you the best support.
Good luck on your search for the right yak. Bottom line is, the best one is one you fish out of.