Quests are great. Really light, I can carry mine up a flight of stairs with ds still in it! Fold small, have a carry handle for when it's folded which is a god send if you travel on the train with luggage a lot as it's very easy to carry- much easier than the shoulder strap on the Triumph I thought
I dont have a basket at all on the quinny so a small one would be a bonus The only downside I can see is that the britax is ok from birth, and the quest isnt (3 months i think). I can also get a car seat to go on the Britax but not the Quest.
I got a Quest to use with dd from 8 or 9 weeks iirc. But I wasn't using it much at all, it was literally to take her to and from nursery. I think for light use it's brilliant. Could you get a sling to use until the 3 month mark?