I do the same, but spend more time kiting then SUP and in the dead of it, im out in 35 water and 35 air. I've had a lot of different brands of wetsuits in the past. Currently we are selling Mystic wetsuits. They are standard with the rest of the companies. What I find is the more high-end wetsuits have more mobility, flex and more overall comfort and internal softness. However they lack in durability due to the cushy neoprene materials. The mystic Majestic is the high-end suit the 5/4 back zip retails about 400 and is super soft super comfortable and you would never think you got on 5/4. The low-end 5/4 is the star (retail 200); this suit is more of an itchy neoprene and is not as cushy but is more durable in my opinion. I recommend the star for beginners who are going to treat things a little more roughly and the black star or majestic for guys looking for something a little more soft.
And like mentioned you could always do a Ocean Rodeo Soul dry suit...which i got it stock this year and look forward to trying. Check out www.AtlanticKiteboarding.com
for more info...possible discounts for forum members.