synth is preferable for rock climbing i find because ...
- if you get caught out in the rain, just layer it with yr rain shell ... im sure some people here will yadda bout down being perfectly fine in a rain storm on a wall ... IMO theyve never had to do multiple rappels in the pouring rain and the waterfalls that cracks become
- 100-133g/m primaloft is good down to no lower than freezing ... ie micropuff, EB igniter ... 60-80g/m is good to no lower than ~40F for me
- get something with a hood, makes a huge difference in warmth on windy belays
- its very possible that youll get tears or holes at some point ... im sure that there are some people who have never scrapped their belay jackets climbing ... i say the same thing about seat belts, ive never gotten into an accident requiring one, doesnt mean i dont wear it .... if you tear your synth jacket, just patch it up when you get home ... if you tear yr down UL jacket, watch the feathers fly!