A 46 F bag is not enough even during the summer time in many (most) places. If you want to backpack with it you will have to pay extra to make it light weight enough to carry well. If it’s going to ride around in the car a military surplus one or a big heavy cheap one might suffice.

I’m looking at getting another bag this summer for backpacking and have been reading good things about the Wiggy’s bags, which I hear the military now uses. My local climbing store likes the Mountain Hard Wear ones and speaks well of them. All other things being equal higher cost will make the bag lighter and more compact.

Down is more compact but losses most (all) of its insulation ability if it gets wet. Synthetics are bulkier and heavier (on average) but will still keep some warmth in them if they get wet. Wiggy’s are supposed to excel at keeping you warm (alive) when wet.

Any way that’s my 2 cents worth!