IR is affordable and "good". Kokotat is expensive and "the best". I have no ill will with IR and feel they are fantastic for all kinds of stuff. That being said, the Kokotat dry suit is just simply superior, and talk about customer service... it's very much top notch.
Here is my only complaint about my kokotat dry suit and it's hard to articulate without showing you... That front diagonal zipper goes down below the skirt tunnel. Water easily drips down that diagonal zipper down into your boat. You don't get wet, but your boat will get more water in it then usual. Kind of a bummer when you are used to a super dry boat. Small issue when you are talking about being dry on the Grand for 2 weeks. Get it... you will be super stoked.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body. But rather...To skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming... WOW !!!! What a ride!!!!!!"