Once you are old and arthritic, you will appreciate a two piece suit. And unless you are nick-named Horsey, you might find that it is easier to take a leak when wearing a two piece suit. (I am thinking here of male anglers...)
Salus has top-notch stuff, and they are Canadian as mentioned above. I have their floater bibs, and an older Canadian navy surplus top. When that top's time is done, I will be buying a Salus top to replace it.
I have not tried the FXR floater stuff, but have a pair of their rain pants (bibs) and I am delighted with them.