Another thing that almost no one would probably be aware of unless you've owned both models is that the Metrolite has changed in design pretty sigificantly. I just snapped some pictures of both the original frame/design and the recent model so you can see.
I figured this would e useful to anyone buying parts to know... I don't think the fabric and some parts are compatible with each other.
They have made the seat MUCH deeper and so the tray sits MUCH higher....great for older kids and their knees but now their feet drag on the floor. My older one doesn't have good legroom for a 4 year old but the tray is a MUCH better heigt for a baby. The basket on the old one is much bigger also.
I took a 16 month old for a walk in the newer on the other day and she kept hitting her head on the tray. The newer models also have a pull strap the adjust the back and it does not stay up at all...she was pulling herself up by the tray the entire walk. My black on has a bar adjustment like the Quattro and sits up nice and straight and there is no way for a baby to smack their head on the tray, it sits at just the rght height. I'm kind of surprised how much I like the older model... it seems they weren't really thinking when they redesigned it and cut a lot of corners.
Rubber wheels
Plastic wheels
The canopy seems a little dfferent and the entire back of the seat, basket and wheel assembly is completely different.