Merrills are shoes, and therefore lower on my list of go-to minimalist footwear for running, but they have had some good uses.
First, I just prefer running barefoot when possible. When not possible, for longer trail runs especially, when rocks and sticks just start to wear on my feet, I like huarache sandals, where my feet can be in the open air, but I have a minimal rubber-ish sole. Huaraches just don't work that well in wet weather though, and so, being from Michigan and Oregon, I've used Vibram Five Finger (the traditional KSOs) as my go-to minimalist footwear for most of my longer races.
What neither huaraches nor VFFs are good for though, is cold weather running. And that's why I bought a pair of Merrills. I was looking for a minimalist footwear that offered a zero-drop heel, while also covering the feets. And, for this, they work very well. As I wrote before in the race report on this blog, I ran a trail marathon in Winter in Michigan, temps just around freezing, on packed snow trail, wearing just the shoes, no socks, and my feet were fine—snugly warm.
The other big thing I used my Merrills for was when, two Winters ago in Portland, Oregon, I was training for Badger Mountain 100 Miler in the Spring. For my long training runs, there was no other footwear that offered what I needed: warmth. Though I will say that Merrills offer both a durable foot shell in general, and some traction on the soles, for the very muddy trails in Forest Park.
I like the way these shoes are designed: they 'grip' or 'hold' at the mid-foot, around the arch, and at first I didn't like that feel because if felt too 'arch support-y'. But it's not, and this allows the area to the front of the foot to be wider: my toes have plenty of room to spread out, without the shoes slipping forward and scrunching them up.
They are shoes, and shoe-ish, so I do not at all like to run on pavement in them. They do limit foot sensitivity, like typing with over mitts on my hands, and I find myself falling back into heel-striking if not careful. For pavement I run barefoot, or with super thing Xero huaraches.
I do use these shoes for occasional regular streetwear. If I need shoes, and the occasion is not too dressy, then I'll put them on. I don't use socks though—if I did they'd bee too tight, and I don't like socks anyways—so they (like the Vibram Five Fingers) can get smelly. Sometimes really, embarrassingly, bad. So if you want them for wearing around town, get a size up if you plan to wear socks. Also: I will wear them for biking around town, since my pedals tend to tear up my moccasins.
Also, if you're buying them in a store (which I recommend, because the sizing is slightly different than 'regular' shoes) make sure the salesperson actually uses them herself, which might actually be rare. Also note that minimalist shoes like these are now usually being sold as trail shoes, with the idea that one should use 'regular' running shoes for street running. Which, is kinda true, but for the wrong reasons: they're 'trail shoes' because barefoot runners might want a little bit of protection on rocky trails.
One more note: in my quest to find a pair of men's minimalist dress shoes, the kind I could wear with a tie (ack) and dress shirt for an interview, say, I bought a pair of black Merrills. They apparently don't make this model anymore, or at least not in black. They still look a little running shoe-ish, with laces, though I don't run in mine, and I have in fact worn them to interviews, even with the laces. I'm not sure if that affected my chances or not, but I didn't ever get an offer. But, for a night on the town, especially in Portland rain, and so as not to embarrass my date by wearing worn down moccasins, I've worn these.
So, if you're a barefoot runner, these might be good for cold weather trail runs.
If you're a regular running shoe wearer, but looking to try minimalist, first I'd recommend running barefoot first. Do not run in Merrills, or any minimalist footwear, in the same way you'd run in evil bad normal running shoes. The heel strike will mess up, badly. As will the longer stride. And, mostly, take these out on the trail.
And if you're just looking for a good sporty minimalist shoe to wear around town, these will do. Much better than any non-minimalist shoe. Though consider moccasins, and/or something like Soft Star Shoe's new model, The Portlander.