Your answer may vary depending on who you ask...
Personally I don't think there's much difference, except the temporary platform is wider than the actual platform at Bridgeport, which is nice when there are 11 billion baby strollers, etc to dodge. Then again when I ride, it's Naugatuck-Devon/Bridgeport-Stamford-Fordham, so I'm taking 3 different trains anyway. A change of trains is a change of trains.
A couple weeks ago a lady got on in Bridgeport and was absolutely incensed when the conductor told her she had to change at Devon to go to Waterbury. "Why should I have to change trains? This is an outrage!" If you're used to getting on at Bridgeport, riding the one train and being done with it, I see it being an annoyance, but not to the extent this lady was carrying on.
The conductors have done a fantastic job warning people WELL ahead of time of the change in transfer points. (One train they started making announcements at Westport about staying on the train to Devon and switching there.)
I'm more concerned with the pipe dream of a permanent Devon Transfer and more service on the branch than this temporary charade
Change at Bridgeport for service to Derby-Shelton, Ansonia, Seymour, Beacon Falls, Naugatuck and Waterbury