Frank S.wrote a review of Outdoor Research Mt. Baker Modular Mitten on March 27, 2015
Familiarity: I've used it several times
Fit: True to size
First a disclaimer: For any glove, warmth is subjective to the individual, and highly affected by the activity for which they are being used. Plus, one's level of exertion can affect actual and perceived warmth, and result in alternating periods of comfort, chilling, overheating, sweating, etc. When holding various gear, insulation compression combined with loss of heat through conduction can also have major impacts. Thus many reviews of gloves are biased by unthoughtful impressions of a bad experience where the user did not consider all of the impacting factors.
With that in mind, I recommend these gloves to be a useful component in a well thought out strategy for keeping ones hands warm in cold winter conditions. I live in the Adirondacks in NY state, and get out into the mountains for (sometimes multi-day) winter hiking, ice climbing, and ski-mountaineering, whenever I am not skiing in northern Vermont. The winters here are brutal, some of the coldest in the country, with temperatures often in double digits below zero, not factoring wind chill. With elevation, temps drop further and winds increase dramatically. I was out many times this winter on -40F wind chill summits. Then put an ice tool, ski pole, or cold aluminum ice axe shaft into your hand for a few hours, and you will find any pair of gloves seriously tested.
I've struggled for years to find the right glove combination, but have found a system that works through the variety of harsh conditions in my local ADK playground...and This OR Mt Baker Modular Mitt is an important part of it! Another component in my system is TWO pairs of Black Diamond Mid-Weight Glove Liners. They are made of Polartec Powerstretch fleece, dry fast and go for about $19. The final component is a pair of Hestra Primaloft Extreme Mitt Liners. They're supremely insulating, and can be had for $55 on sale. Final price of the whole system is about $210...pricey, but well worth it, and you will never be wanting in any situation. Thus your last glove purchase, ever. The versatility of this OR mitt is that the insulating glove can be separated out to leave a completely non-insulated seam sealed Gore-tex shell with very durable face fabric. This means that when/if your insulating layer gets sweaty, you can swap it out for a dry layer that gets inserted into a completely dry shell. Too many other shells incorporate their own integrated insulation that remains behind even after the inner layer is removed, meaning that moisture in the outer shell is something you'll have to live with, and also greatly decreases drying time, which can be critical for multi-day winter endeavors.
The insulating red glove in this OR Mt Baker Mitt has a generous amount of Primaloft on the back of the hand, and when stuffed inside of the shell is a very cozy combo for easy walking on an average winter day (-5F to 20F). There is no Primaloft in the palm, so conduction from an axe handle can be an issue. The grip patches on fingertips afford good dexterity to do most manipulations without exposing hands to severe weather.
In my system, I will use just the BD liners for mild conditions, or during heavy exertion. They are surprisingly warm, but the wind goes right through 'em. Solution: throw just the shell over the top to keep the wind out, greatly increasing warmth. Getting colder? Put on just the red OR liner, or red liner plus shell. You get the idea.
Now, when trying these gloves on, I fit comfortably snug in size medium, but I got a large. They're roomy enough to fit the BD liners into the red insulating layer, allowing extra layering combinations, both with and without the outer shell. And also adds a layer of bulk to protect palms from conductive heat loss when holding stuff. But the real beauty is in managing moisture. When one BD liner gets moist from normal skin transpiration I swap it with the second pair, clip to my backpack, 30 min it's dry. The Hestra Mitt inserts are the ULTIMATE insulation, and can be used with the shell and BD liners to -40F