Anyone have any experience with them?

No, sorry.  But if you're looking for a cold-weather long underwear type baselayer, you might try fleece pants.  I wear them under my waders for winter steelhead fishing and they work great.  I wear a light pair of zip-off type fishing pants over them, and it's very comfortable.  The fleece is good in case you get wet; not that that ever happens to me while wading in an icy steelhead stream...  Also works well under raingear on a cold fall or spring day in a canoe.  I don't even own any long underwear anymore.

OS- the merino has the itch out...the wool fiber that you grew up with have small "scales" that are removed through various processes. Those are the buggerg that make the itch as they irritate the skin...

Terry-been running wool and plastics in baselayer forms for years...pros and cons to both. Plastic a bit more durable but then one has the funky fragrance and "oil". Wool is pretty much funk free, a different kind of warmth (drier IMHO), but the fiber is more fragile...and the merino garments are a bit more pricey.

So ergo the wool power query....they are one of the few that use a blend of plastics and wool in their base layers. I like the wool but the durability, costs, overall greenest are taking away from that dry warmth looking for an improvement  or maybe I am just splitting hairs so to speak....just saying.

Marlin,
I bought my wife an Ulfrotte (which is now Wool Power) turtle neck top in the base layer weight a number of years ago.  These are my comments based on my observations:

Durability:  It seems to have held up just fine.  She only wears it occasionally now in the winter, but lived in it 24 hours a day during an extended trip in northern Manitoba and on sporadic trips since then.  It looks nearly brand new.  The weave isn't particularly tight, and there are little loops of fabric on the inside that seem like they would easily catch on branches, twigs, zippers, etc and pull.  However, this hasn't occurred based on what I've seen.

Warmth:  Heard good things.  Dries faster than pure merino.

Fit:  Seems good, though I think it has shrunk a little over time, even though it is washable.

Odor:  none, although my wife doesn't stink like I do

Campmor has Smartwool stuff 20% off right now and free ship over $100

Thanks for the info AP....

Jim-so true the wool is naturally fire resistant.

Smart Wool....Been running Smartwool for years, both socks and baselayers. The initial experience kept me coming back...but recently the baselayers have been somewhat disappointing from the durability perspective...I have gleaned: this is an inherit issue with the fiber/textile. Still curious as to why I am seeing it now after so many years What I am seeing is that the garments get to a point and just disintegrate, darning is not the solve The use has been uniform, so the fiber issue is sort of mute but the construction is suspect, sorry Rep. That is why I am on the search...for garments that are of the hybrid persuasion, wool for the natural warmth and such and polypro/capalene for the strength and hydrophobic features...woolpower, mountain hardware, and patagonia are the possibilities that I have gathered so far; and woolpower I know very little about both in company and design. Just picked up another set of smartwool for my control in the adventure and discernment.

DB...justa notion...try a second rinse and mind the bug dope. Just a notion mind you. The burn is suspect, and a "control" may yield the knowledge you seek or more questions for sure. Do you use that Pyrethrin based log lasting garment applied bug control?

DB,
 It's not just you, I have the same problem. Poly does'n bother my sons, just me. I now use a cotton t shirt as a buffer.
Reguarding socks,  I've been using military surplus 100% wool socks for the last 9 years. The itch doesn't bother me, but drives my buddy nuts. I watch the surplus sales and pick up a dozen at $20. Not sure what country's military uses them.

Merino wool has made cold wet October trips much easier to bear. I've found this brand (You need to Login or Register to view media files and links) to be virtually itch free and very durable- no holes or tears despite a year and a half of hard use (medium weight zip).