If there's a few drawbacks then why not 4 or even 3 stars? Well, let me explain...
These sandals are fantastically comfortable and if you get the bison leather, they're actually stylish enough to wear out (well, stylish enough for me, anyways...some might disagree).
Comfort is a 10 out of 10, without question. Really, really nice.
Convenience is a 8 out of 10. Even with the leather ones, you can get them wet, get them muddy, jump in a lake, do whatever you feel like with them. All it takes is a spray down to get stuff off of them.
They get an 8 because of the funk factor - they need a soap every once in a while because they will get a little ripe. If your feet sweat, these sandals don't have quite enough ventilation to let it all out. The footbed is apparently anti-odor and, all-a-round, is about as good as you can get. If you have sweaty feet, you'll need to wash them, but washing them is easy. The lack of ventilation is what must be traded for the support and comfort these sandals offer. It's really not that big of a deal.
Use for hiking - well...that depends where you're hiking. Trails and rivers and things, they'd probably be 10/10. If, however, you are hiking anywhere with sand you need to leave these at home and herein lies the one flaw with the sandal: stuff that gets in the sandal does NOT get out.
This is because of the toe design which is great for, well, not hurting your toes. But when a rock gets caught in there, you've got to stop and take off the sandal to get it out. If you don't mind stopping occationally to take them off and shake them out, there are no problems.
This flaw also brings up one other minor, but possibly relevant, point to a certain demographic. If you are diabetic and are attracted to these sandals because of the toe guard, you need to look elsewhere. The toe guard is great, but if something gets caught in there, it might not be noticed and a rock in this sandal all day could do serious damage to diabetic feet.
Other than the rock thing, I couldn't ask for anything more.
With regard to the bison sandal - after they get wet a few times, the leather will start to fade a bit. If you like the color it fades to then never mind. But if you want them to look the way they did, I put some Doc Martins wonder balsam on them and got the same dark brown color they came with, no problems.