A few of my friends have Transit Connects. One bought one a few days ago. It's the minivan for guys who don't want a minivan. The side effect of that is it's compromised as a minivan. It's also smaller - even the LWB model has a cargo length of 87.6". The GC can get a 8' sheet of plywood inside. Another thing - the 15.8 gallon fuel tank would be a PITA for the driving I do (the GC has a 20 gal tank). And the V6 in the GC has a lot more power with similar fuel mileage. Lastly, the Connect lacks two features (not even shown as options) that I use in my GC GT a lot - remote start and heated steering wheel. Two things I never thought I'd care much about, but now that I've gotten used to them I wouldn't want to go without them.
The Grand Caravan GT was a fleet trim sold mainly to rental companies. Mine was an ex-Enterprise rental. It had just under 25K miles on it when I bought it in July 2018. It'll pass 70K next week. So far I've done nothing to it other than oil changes and a set of tires (since I didn't like the cheap ones it came with).
I have another van as well - a giant 1992 Ford E-350 extended length, raised roof conversion van with a 7.3L IDI (non-turbo) diesel. I bought it a couple of years ago to convert into a bike-hauler and camper. However, I've come to realize I simply don't have the time nor space right now to do that conversion, so I'll be selling it soon. It'll go along with my 2003 TDI wagon, which I haven't touched in about 6 years. While I'll miss the ~50 MPG of the TDI, as mentioned - gas is cheap right now. And the minivan serves my current needs better. I have my 2006 MINI (along with the aforementioned GT6 as well as a Spitfire) when I need to scratch the "drive something fun" itch. But as a pure appliance, the minivan is hard to beat.