Merino wool is indeed lovely stuff. And I bet there’s a lot of it available in New Zealand - after all that’s wool country. Overall, wool has similar properties to good synthetics, and when I started outdoor stuff, lo these many years ago, wool filled the same clothing niche as synthetics do today: It was the stuff you packed that could keep you warm when wet.
Modern wool clothing is lighter, softer, less itchy than what was available 20 years ago. It’s also very durable. The smell bit I’m not sure about. Certainly, some synthetics bond to smell molecules (I’m not kidding!) making it very difficult to wash out body odors. But those tend to be older synthetics my silkweight Patagonia T-shirt has been sweated through dozens of times, and is fresh as daisy after a good wash, just like Yours Truly. The big downside to wool remains the fact that once it’s wet, it stays wet for a very long period of time, adding weight to your load.
In the U.S., the company that has carved out a niche for itself with wool clothing is Ibex (www.ibexwear.com). That company’s Norse Crew is a Merino shirt in a long-sleeve T design that’s probably a lot like Icebreaker’s Superfine clothing range. The Norse Crew is $72 - so cost is an issue versus a decent midweight synthetic such as Marmot’s midweight T, which is $45. But it’s fine clothing, and probably should get more attention.