A 14ft boat will draft less water than the smaller boats and should maneuver about the same. Boats over 14 ft are more designed to haul cargo and will be a bit more sluggish on the water. I'd go with the braces if the fisherfolk will be casting while the boat is moving. If you only cast while at anchor, then it really doesn't matter.
As a reference, I purchased my first raft about 6 years ago. It was a nine year old Aire 15.5 ft with a whitewater frame, casting brace, two dry boxes, cooler, and cataract oars for $3,400. Bomber boat that I've taken on well over 3k river miles including GC, MFS, Selway, Rogue, Illinois, etc. Not one issue other than a sandy valve from time to time. Found a used raft trailer in excellent condition on CL for $800.
The boats I'd consider if purchasing again: Aire (Tributary lower quality materials made overseas, Outcast), Sotar, Maravia/Streamteck, NRS, and Hyside. From there, the material and build quality diminish quickly.
My .02.