H.W.
Personally, the only thing I was willing to push my son around in was a stroller. There's something to be said for letting them develop at their own pace, develop the muscles to push themselves.
Just looking at the Step 2, this is what I see: a trunk, which can be loaded with toys, which the child will then want to access while on the walk--because older toddlers are like this (causing conflict); a backache getting the toy up/onto curbs; body pain from pushing this big toy with your child on it (consider the added weight) with one arm while trying to manage doggie with the other arm.
The fact that it has a seat belt suggests that the kid may not be ready for it. I don't mind seatbelts for cars or strollers, but the idea that a child needs to be belted on a riding toy?
I worked in childcare for a long time-- those are the foreseeable negatives. The Cozy Coupe will help your kid learn how to get their legs in and out of the vehicle (lifting them higher), the kids like the door, and your kid does get more of a chance to use their legs and move the toy around, developing strength in the legs. We had these with our older toddler groups on the playground. Probably not great for a walk, but fun for home.