Complicated question. I guess it depends what you want to use the boat for and what trade off's you can live with (assuming no boat is absolutley perfect.
I had a 29 Southport and moved to a 336 Canyon. I looked at many boats before the move and seriously considered YF, Sea Vee, Bahama and GW 366 (but I didnt want to go to triple outboards so that kept me in the 34' range). I was also very intereseted in the Southport 33 but production kept getting stalled (it is avilalable now) In my case, from the length to beam experience with Southport, I recognized the advantages of the length to beam ration (29' x 10' and deadrise) so the 336 won out there (although the Bahama has a great ratio) I use the boat inshore and out to the NE canyons in summer and fall so stability at drift and weight/ride in open ocean were big factors, our weather changes quickly iin NJ//NY- in reality, it is not very often that you can go 40,50,60 mph offshore for 2-3 hours without beating yourself and the boat to death. I was willing to sacrifice some fuel economy and speed for the beam and weight. I found the fit/finish/layout of the GW to be great- in order, i think Sea Vee, Southport, Bahama all have great fit/finish and then YF for fit finish and layout. It is also hard to find the creature comforts on a 336 in other mid size CC's (genset, freezer box, insulated boxes, all boxes drian overboard, and the well thought out/functional layout - these were all important to me but may not be important to you)
I have to admit, I was not big GW fan ,prior to this GW purchase (I thought the owners were more of a cult) but my first offshore in the 336 went sour- seas went to true 7-8' with winds off starboard bow and 15-20+ knot winds on our nose for 70 mile ride home - I was really impressed- maybe the other boats would have done as well (but I dont think so) the weight, beam and hull handled the ride extremely well..
I think you cannot go wrong with 336, Southport, Sea Vee, Bahama, YF- they all appear to be good boats- I was very impressed with my Southport as is all owners and the bahama is a beautiful, well laid out boat (but they donrt have gensets, freezerboxes, etc)I think it depends how you use the boat (cruise vs.fish) where you boat (inshore vs canyons) and what features are important to you. I can tell you, I am extremley impressed with the 336 as is everyone that rides on it. if you want moe info, I can send cell number and we can talk.