I have the 236 for several reasons.
1) The higher gunwales offer much more protection for my 6year old son than the 251 CE does
2) The big aft fishbox is really nice either for loading with fish for fishing trips or gear such as tubes when playing at the lakes
3) The aft swim platforms on the 236 are amazing!
Both models have the identical console and leaning post (I have the updgrade leaning post with livewell on my 236). With the back livewell, I have two really big livewells at my disposal.
Note GW used to make a 191 CE which is no longer available.
Also, my dealer never even considered showing me the 251 CE. Mostly due to the younger family. It was either the 236 or the 235 Freedom but I mainly fish so it was the 236 all day.
The only thing I like about the 251 CE is the aft-mounted GPS trolling motor. However, I've been told I could get the same spot-lock trolling motor put on my 236. It'll cost me 5k
I fish in Galveston, TX in the bays and up to 45 miles offshore. We also trailer to the Central Texas lakes such as LBJ and Travis near Austin. With the full cushion package she really does well on the lakes! I pulled my wife on a tube the day after Chrismas last year. Galveston Bay is a big bay and anywhere the 25ft guide boats run (which are mostly Whalers), I can run.