I based my comment on the prices I found on the Hallmark website. There version of a shell with similar options added that come standard on a FWC shell, would put it about double the price of the FWC shell. I am glad you are happy with yours, they are very nice!I have no idea regarding the price of the shell models, however I don't think the regular 'built'/optioned slide-in models are double the price of a similar FWC, but certainly more expensive.
Only you can decide if the lack of condensation and overall performance is worth it, money and value is a personal thing. However, I have been very happy with my Hallmark campers. Cold weather performance/insulation is very important to me.