If you want down then
Decathlon down is excellent value and pretty hard wearing mine is three years old and is still going strong,plenty of weights to choose from
Uniqulo pretty decent but not as good value for warmth but better colours
Alpkit the older large down ones are very warm, but bulky. Lighter ones i think the decathlon are better value,
Arcteryx i have a synthetic down mix and i would not bother paying the premium again, no warmer than others and not a great fit either but big street credit.
PHD pretty much as good as can get in down, not always the best cut so choose wisely. I like mine but ….See below
Jottnar i got one in tk maxx and was impressed but gave it to my older brother who adores it, ex builder, very very warm, very well made.
I would not both with down yes packable, light but synthetic is a better more robust alternative if it is so good used in the wet, stuffed in and out of packs, easy to wash and dry and used in British wet humid muggy climate.
Of the ones i have i would recommend
Decathlon simond/ their mountaineering range, great warmth and really robust. But the sizing are a bit all over so need to try.
Rab generator, i think bought off here and pretty impressive but a box body cut so lots of space but good for fitting things under.
Alpkit synthetic, my daughter swears by hers warm, robust, and been seriously mistreated yet looks good. I found the cut too tight round my shoulders arms but good in body.
Finesterre gilet, i have one bought second hand and trashed for the last seven years just keeps going wash after wash.
TK Maxx have lots of random things in but got a Rock Experience (Italian brand) for 15 quid been great.
I avoid montane as the cut was too short and the prism not that warm.
I avoid Patagonia as the cut is not the best for me.
My ultimate jacket is a black diamond hot forge bought this winter gone for 120 quid a mix of synthetic and down, great fit great warmth great weather resistance and stolen last week when i was in Madrid, gutted.
Good luck
