Hi,
Cant answer in terms of the comparrison - but i do have the quattro deluxe.
it IS a heavy pushchair - but i LOVE it!
It is only heavy to pick up ( to put in your boot for example) it feels really light when pushing IMO, it is really easy to manage i think. I used to use it with the car seat on the pushchair - and this week, LO has been forward facing in just the pushchair part (and loves it) and it makes it even easier to steer!
If you live in a flat, or use public transport, then i would say the Graco is impracticable, but cant say about the Luna sorry!