I've been in both, and own the SeaClass 14. If you have any distance to run, or may get into some snotty water, you want the SeaClass. If you don't have a long run, hunt alone mostly, need 2" less draft, and aren't in a hurry to get there, and need a bit more concealability, the Classic will suit you better.
I have a 25hp Mariner on mine, and loaded with two guys, dog, 1.5dozen cork and cedar dekes, dozen goose floaters, 2 big river anchors, 2 10# mushroom anchors, I don't have any issues getting on plane.....now....I added a tail last year and dropped the prop pitch this year.....plane at around 22mph WOT
My advice is this: if the TDB brand is what you want, pick the model that suits you and just buy a new one from Arthur Armstrong. You are going to have an extremely difficult time finding an SC 14, and if you do, you are going to pay several thousand more dollars than it's NADA and insurable and financeable value. The prices on the classic style are out of wack as well, totally insane actually. The AA built SC14's are rated for 40hp as well. The Maine boats are tagged for 25hp.