hi,
I was faced with a similair situation and there are some stroller Gurus who will chime in also Im sure.
Are these the only strollers available to you first of all. I chose a BOB over the MB Duo seemed like it had the biggest seat. I would definitely choose a DUO over DUET. The seats are bigger and for a four year old in a snowsuit it might be the better choice. I looked at the Valco but it cost more, couldnt find a deal on CL, and resale in my area made the BOB(new) paid 450, a better choice. The canopy height was tallest in the Valco. I would definitely choose between the MB duo, Valco Trimode or A BOB if it was up to me.
The BOB has a 70% recline so it is not okay for newborns. Its suggested to wait till 2 months and probably use a snuzzler still. The MB duo/duet and the Valco are suitable for newborns. Duo/Duet has a bassinet option also. Trimode has a bassinet -ish insert available husah? I think its called. Is the trimode an EX? They are the latest available and have better sun coverage.
Im in luv with my BOB. It has the best push. It is not fun to lift but folds up small enough for my volvo sedan trunk. Trimode wont fit, I tried even with wheels off. Good luck. Hope this helps.