Just saw these (and got some) at my local Costco. Ok, so some folks might think that 11% Merino wool is a gimmick, and casually speaking, that makes sense.
But, they don't really add the Merino for odor control, but for feel and some absorbency. Dri Release stuff does some interesting micro yarn blending, wherein often times they use a predominant synthetic core of fibers, which are wrapped on the outside with some natural or semi natural, absorbent fibers like wool, silk, tencel, cotton, etc.
The feel of the fabric, because of those small amounts of natural absorbent fibers but on the outside (creating a bit of micro space between the skin and the synthetic fibers) does feel more natural and nicer than a lot of synthetic shirts.
The point is the feel, but more so how it handles moisture. The minority percentage of natural absorbing fiber on the outside, does some initial absorbing of moisture, but when that moisture gets to the synthetic core, it wicks it outwards speeding up evaporation. It's pretty darn good at this, though maybe not quite as good as say power dry stuff.
Fresh Guard is what helps to control odor. Fresh guard is apparently an oleo-phobic coating that goes on the inside synthetic core of fibers, and since it's more on the inside of the yarn, it will last a much longer time if it was say a more surface coating.
The wool contributes very minimally to the odor control, it's primarily the fresh guard stuff that does this. It would be interesting to see if there is any difference at all between a Dri Release Wool or say cotton blend as far as odor prevention goes. I suspect there wouldn't be any noticeable difference at such low ratios of natural fiber.
In actual experience and practice, i would say it works decently to good. Definitely a lot better than your typical 100% and non treated synthetic, however, not as good as a 100% Merino or 100% Linen fabric. I have not tested the uber expensive treated 100% synthetics that some have recommended here because, well i tend to have a lack of spending money.
Anyways, i plan on testing one of the shirts a bit differently. I rarely get to do extended backpacking trips, and usually my longest are 3 days. So to make up for it, i'm going to wear one of these continually day and night for a week, with jogging (and working up a good sweat) every other day, to see just how good or not the Merino Dri release works.
Oh, can't forget weights ;) The pants in medium weigh a respectable 5.6 oz, and the shirt in medium with a high collar and quarter neck zip, weighs 8 oz.
