I have a montbell ultralight down vest and a Western Mountaineering Meltdown jacket - love them both, and highly recommend both brands. (Feathered Friends and Nunatak are good as well, and then there are a lot of fine brands in the next tier down, including Mountain Hardwear and Marmot and even LL Bean).

I also have some synthetic vests and jackets - mostly from GoLite, which I picked up on clearance. More on that in a second.

I think the vest vs jacket (and hooded versus non) choice comes down to personal preference and climate. Vests save a bit of weight and volume and are fine when you aren't in extreme cold or if your arms tend to stay warm - they're also a little better for use when moving.

Down fill power: obviously the higher it goes, the lighter the garment for the same amount of loft; however, the higher it goes, the more careful you have to be about keeping it dry, as in my experience the higher fill powers take less moisture to collapse.

Regarding down versus synthetic - if you're only out for overnights or day trips, down will likely be a fine choice pretty much always; for longer trips in challenging wet conditions, or where you're on the move wearing the layer and might sweat into it even in extreme cold, the synthetics get a nod.

I use my montbell down vest most of the year outside of snowy conditions, and pair it with an ultralight windshirt. Great combo. For snow camping, I bring the Western Mountaineering jacket, or a combo of a GoLite synthetic vest and a synthetic fill parka; I can wear the vest while on the move or at quick stops, and save the parka for when it's really cold at night, often wearing both layers together. I've sized all of these items so I can wear an Arc'teryx GoreTex shell over them for extreme weather.