I love mine
I don't know what the best system is, but I love mine. This is the one I have:
It's really easy to open and close the stroller and the car seat base was easy to install. It's just a simple one hand lever pull to unlatch and take the baby seat out of the car, and the same for snapping it onto the stroller. The only downside I would say is that the baby seat is kind of heavy, so as he's growing it's getting a lot harder to carry it around, but I usually am only carrying it for a short time anyway. For long distances I put it onto the stroller or if I'm in a store on a cart.
The baby seat part also can be rocked, so it's come in handy so many times soothing my baby when he won't stop crying. He loves the rocking motion of it.
The price is pretty reasonable for what you get too which is great.