Hi, Lauren,
Well, you are kind of trying to go from one full size, pretty much HUGE pram to the smallest possible. Watch out, as ultra-compacts (more about those here) you are trying to pick from are occasional strollers, not at all all terrain, and narrower in the seat, overall smaller in most aspect, even the functional ones.
I must warn you here, the difference will be great - but not only in the good things (like a MUCH smaller pushchair), but also in the worse ones, like the push, the space, the sturdiness. The Metro+ is a good choice, actually, so if really having to have such a small model, it is not a bad pick. Again, the ride will be harder, with much less suspension and comfort features. So if an ultra-compact stroller is your go to, you picked reasonably well at that price point.
On the other hand, my personal recommendation would be something slightly larger, a lightweight forward-facing mid-sized pushchair will be MUCH comfier for your little one and will last you better while still MUCH smaller than the Pioneer, especially with everyday use in mind. An Oyster Zero, Valco Trend, Baby Jogger City Mini will be a better choice here, from my opint of view, but that is of course food for thought for you and your family/lifestyle.