hooah -
My signature speaks words of many wise men (and many men with MUCH bigger boats than they need); "buy the smallest boat you can be comfortable on, not the biggest boat you can afford".
For 4 people, I'd agree that a 14' is probably the 'sweet spot', but it's all going to come down to beam measurement (width).
My 12' tinny is actually a commercial fishing model with a whopping 64" beam :shock:; many buddies feel as I do, that she fishes much more like a 14-16' boat, yet is much more maneuverable than a longer/larger craft. I can easily fish with myself +2 other adults, and often go out with 1 adult +2 or 3 kids depending on how small they are.
I often troll for boats on Craigslist just to see what's out there and if they're any gems, but usually what I find falls shorter (more like narrower) than what I'd want. As was mentioned before, I think in most markets you'll find there's a big price jump between 14' and 16', not to mention that you'll need more power (both gas power or electric) to move a larger craft.
If money is no object to you, I'd look at some of the 16' all-welded (no rivets) models, but they're pricy and heavy (there's that more power thing creeping in again).
Anyway, let us know what you find, and, GOOD LUCK! :mrgreen: