I'm not a kayaker, so I don't personally know how the bibs/dry-top system works for kayakers...but this alternative is good for a cheap option, especially if you already have a dry top. I took a lot of swims this last year in my system, and never got wet through the roll.
My bibs are Kokatat Tropos...so I can comment on that fabric. It does not breath at all. I would get hot and sweaty when boating in 36 degree water and 40 degree weather. So if you're going to spend the money, get something better. It will cost more but you'll thank yourself later. As for durablity, I wore them everyday over the summer and they're still in good shape (expect for where my oar went through them, but that was user error, but a defect in the material)