The problem with the CEP refurbishment was that it was so heavily based on 1970s / early 80s trends, such as extensive use of orange and yellow, exposed fluorescent tubes, light-coloured walls etc. If you go to some of the living museums around the country one can see how this was very much the “in” decor for kitchens and even living rooms for a while, but it quickly became *very* dated.
I can remember my grandparents kitchen as it was in those days, and it bore much similarity to the refurbished CEPs. Lemon yellow Lino floor, white formica units, orange curtains and plain light-coloured walls, and of course the customary bare fluorescent strip light. Even by the 1990s it seemed pretty dated.
By contrast the VEP/CIGs didn’t lean too heavily to this, in fact they retained 1960s finishes which were a lot more neutral, and seemed to suit trains much better.
Same with the class 205 and 207s. Thankfully these were never heavily refurbished and therefore kept their older ambience to the end, whereas the sole refurbished unit was quite oppressive in the same way as the CEP refurbishment. We dodged a bullet there.
The other problems was the window seals perishing which then resulted in them misting up. The CIGs and VEPs never had this problem, though in cold weather they would steam up, but this could be resolved by opening the windows.