I'll be honest, there's nothing like the conveniece of wheeling your children and stroller right onto the monorail (especially if they're asleep or tired).
The busses are luck of the draw. If the bus is crowded, it's tough with a stroller. If the bus isn't crowded, not as bad.
You get a packed bus (Standing room only), maybe a wheelchair guest is on that bus too, you're standing, holding bags, strollers, kids crying, etc... it can be a challenge.
Like the poster above said, make sure you can fold and unfold quickly... most strollers today are pretty easy once you get the hang of it.