The whole idea of wool having the benefit of keeping warm when wet is an over-generalization. Synthetic layers retain heat when wet too. But I think that's often misunderstood, that for some reason a wet piece of extremely thin merino will magically stay warm. Wet is wet and I have never noticed any warmth advantage from wearing a soaked merino baselayer versus a soaked synthetic layer. The 'warm when wet' statement is really only meaningfully relevant when comparing it to cotton, which I think is safe to say most people here don't consider cotton as an option in this context.
Synthetic layers weigh less, dry faster, are more durable, and in my experience are equally warm when wet or dry. I might be on the fortunate side, but I don't experience significant funk/smell after multiple days of wearing synthetic baselayers. That doesn't mean that it can't and doesn't happen at some point. Modern synthetic fabrics have treatments that mitigate bacteria build up and also help transmit moisture away from the body, on top of being hydrophobic, and therefore quick-drying by nature. Merino is much more resistant to bacteria and odor, but it can develop an odor when wet, it's just not a funk odor.
I personally don't really care how I smell in the mountains, so it's a moot point to me. I own and use both merino and synthetics, but tend to prefer synthetic baselayers to save weight and because I like how much faster they dry. Sometimes the dry time makes a big difference in holding out glassing on an exposed ridge after getting soaked in sweat on the hike in. For me, the only real advantage merino has is in odor mitigation. I generally prefer the benefits of synthetic and choose it more often. To each their own, you just have to decide what your preferences are.
Synthetic layers weigh less, dry faster, are more durable, and in my experience are equally warm when wet or dry. I might be on the fortunate side, but I don't experience significant funk/smell after multiple days of wearing synthetic baselayers. That doesn't mean that it can't and doesn't happen at some point. Modern synthetic fabrics have treatments that mitigate bacteria build up and also help transmit moisture away from the body, on top of being hydrophobic, and therefore quick-drying by nature. Merino is much more resistant to bacteria and odor, but it can develop an odor when wet, it's just not a funk odor.
I personally don't really care how I smell in the mountains, so it's a moot point to me. I own and use both merino and synthetics, but tend to prefer synthetic baselayers to save weight and because I like how much faster they dry. Sometimes the dry time makes a big difference in holding out glassing on an exposed ridge after getting soaked in sweat on the hike in. For me, the only real advantage merino has is in odor mitigation. I generally prefer the benefits of synthetic and choose it more often. To each their own, you just have to decide what your preferences are.
