I've used a wide variety (mostly 150 weight) Merino wool shirts for years, and in fact, they are basically the only T-shirts I wear these days. IMO, if you're doing a lot of travel, they are absolutely worth it - warm when cool, cool when hot, wicks away sweat and dries quickly when wet/washed all while resisting stink/BO. I'd have to agree on the cons though - I've paid $80+ for a shirt (depending on brand and country) and have experienced wear/holes sometimes in months (even with only handwashing).