I recently read an German article about merino wool which is well worth reading. I am just posting it here because I know you are German too @Paul.
What you can expect by merino wool (and I think likewise in other kinds of wool) compared to the usual Softshells/Fleece made from synthetic fiber is:
- Durability: okay
- Breathability: very good (better)
- Water resistance: decent (worse if Softshell has membrane)
- Wind resistance: decent (worse if Softshell has membrane)
- Enviromental impact of production/life cycle: low (natural product, completely recyclable, check the source of the wool and therefore maybe animal protection aspects)
Those points above are very general said and this might not be true for all type of Softshells. Which is important is to state the pros and cons of wool. Besides the hefty pricing of merino wool and sometimes bad treatment of the sheep (I think some (most?!) bigger brands changed their strategy and care a lot for this and receive the wool from well treated sheep) I can't think of many cons.
Therefore check the pros
Especially compared to jackets with membranes, wool will be much more breathable and mostly really comfortable.
Compared to synthetic fiber, with merino wool you are getting a clothing with:
- very fast drying
- feels extremely comfortable, also when wet
- actively warms when wet
- cools when warm (not true for the thick jackets you asked for but it is for a shirt)
- isn't prone to attract bacteria, so it won't smell bad that fast (try it with socks, you can wear them several days on a hike and they will smell quite neutral)
- high sun protection factor (50+)
- no electrical loading so it won't stick to the skin
- easy to clean in the washing machine (but you still shouldn't wash harsh clothing with it and you shouldn't use more than 40°C)
(Will check some infos later and will try to make this short overview a bit clearer.)