Wool rocks.
Smartwool products are great, but there are also other options when it comes to merino wool.
Patagonia, Ibex and Icebreaker make utterly superlative products, Icebreakers' being a bit more hiply styled without losing any technical features. Also pricey, import from New Zealand. Ibex is also spendy but top-notch. I believe that inexpensive merino wool is also offered by places like campmor.com.
Everyone seems different in terms of itchiness. I never find any merino wool products itchy, others do until the first wash, others still always find them itchy (the latter seem rare).
Mostly what you need to look for is the weight in grams/square meter. 140-190 are useful for summer pursuits; above that you're looking at cooler temperature use. Wool gets heavy when wet, but insulates when wet (just like synthetics), and they really do not hold odor like synthetics.
I own four Icebreaker tops, two Smartwool tops, and one Patagonia Wool2 top - wouldn't own that much wool if it didn't perform. I still find that on the hottest of the hot days, though, the lightest weight wool is still too much and I switch to ultralight synthetics so they can wick faster and so that the wind can penetrate for cooling.
YMMV, but that's my experience. Hope this helps.
-Atomick