Of course the standard reply is go with the Kokatat (GMER) and you can't go wrong there considering the quality of the construction and the company behind it. There's so many people on here with A LOT of history with it and they're pretty much all good stories. Two of my best friends went that way and I almost did but I wanted something that improved on previous designs and it seems like the biggest complaint on the Kokatat is having a large semi-stiff zipper across your shoulder.
I looked at the IR (my drytop is an X Jacket & it's great as are the IR people). The zipper-across-the-back-of-the-shoulders design solves the paddling comfort issue but as others here have said it's a pain in the ass to get in & out by yourself. (Another friend just grabbed the Palm and likes it but says his wife likes it more because it means he can never paddle alone.
I was going to go with the IR and then I found the Peak. I like that they are actually looking at the older designs out there and came up with innovative solutions. The enter-through-the-legs design is such a great improvement. Getting in & out of the suit is really easy- kind of like putting on a long drytop. It solves the need for a relief zipper for guys or girls. And I guess, technically, if you really wanted to, you could drop the duece still in the suit but I'm not taking a dump in a $700 drysuit. The other thing I really like about it is that it's based off of their Creek drytop design so it's got built-in pockets at the elbows and just below the back of the neck to add their padding (this is outside the actual drytop surface so a strike to the pad would not affect the seal of the suit).
It's built really well. Incredible quality. They've paid attention to details- silicone gripper printed onto the inside of the neoprene on the tunnel to give better grip on the skirt, the neoprene on the wrists and neck is capped & sewn (unlike the kokatat), the gaskets are really heavy duty & cordura on the shoulders, elbows, knees & butt.
So if you're still trying to decide you should check out the Peak UK. They really deserve a look.
Here's the direct link to the suit on their site:
Peak UK - Kit