Whatever brand you get see if they will accommodate a push to talk, (PTT), external mike/speaker like the cops use. I and my buddies all have them and they give you the luxury of keeping the unit in a pocket or on the belt and easily communicating with the mike attached to your wader suspender or wherever.
Also although lots of folks like rechargeable batteries I recommend a set that uses AA batteries. Sometimes when you're camping or fishing an outlet can be hard to come by but you can get AA batteries just about anywhere. I keep an extra set in my vest just in case.
By the way I have and recommend Motorola for their size and quality. I once drown my Motorola PTT mike for about an hour in the stream and after drying out for a few days it worked just fine!