Which would it be and why? I'm talking an all day hike, 20 miles kind of thing.

In the past, I've been comfortable in my Merrell MOAB ventilators, but I don't know if they're up to the task of an all day walk. Then again, I've never worn them for that long a period of time and activity so I can't say.

I do tree work all day every day. I love Vasque and Salomon. I am too comfortable to get off the couch and check the exact names though. Sorry

Asolo Fugitive GTX. Lightweight, waterproof, nice stiff outsole for support, great ankle support, and plenty of lace for alternative lacing methods. I wear mine down to around 15F when snowshoeing, they'd probably be warm enough at colder temps but I've never wanted to ruin a snowshoe trek by getting cold feet so I stick with my Sorels below 15F.

Vasque St. Elias GV are nice, too, but I haven't worn them as much. My previous pair just didn't fit right (before I learned about arch supportive footbeds and what proper arch support can do for the shape of your foot & the fit of boots) and after a few months I returned them. They were nice boots that just didn't fit right. I bought another pair about 2 weeks ago, along with footbeds, and these fit perfectly. They're all leather, as opposed to the Fugitive's suede/nylon construction, and are called backpacking boots while the Asolos are hiking boots, but I don't really see much difference in the construction. They both have good, stiff outsoles & lots of ankle support (the Fugitives may be a little better, at least for the shape of my feet), and those are what you want more than anything else. With typical light hiker soles you'll be feeling every pebble & root before you're halfway done.

Hiking shoes are the in thing nowadays, a lot less weight on your feet for a lot less fatigue, but I don't really like wearing anything that doesn't go above the ankle (boots are all I wear, 365 days a year.)

Two words-

Approach shoes.



If you prefer a high-top

XA Pro 3Ds.

Oboz

Asolo Fugative GTX great boots!

Depends on the season; Vasque Breeze 2.0 in the warmer months, Vasque Eriksson in the cooler months, and some other boot if I need to go with snowshoes.

Mammut Pacific Crest

Danner Mountain Light

Asolo
Meindl
Danner
Vasque

Any of those brands will suit you well.

I have wide feet and the only hikers I've found that fit me wonderfully are Merrell... specifically the ones already mentioned in the OP: Moab Ventilators.


I've had 7 or 8 pairs of Merrell shoes in different styles and they've all been great.

I've really steered away from heavier boots unless I'm humping a heavy pack off-trail (not much of that these days).  Merrell have proven very comfortable for extended, multiday hikes and I've been using Vivobarefoot Tracker boots this last year.  I've had no issues, but read about some poor QA/QC which sucks as the boot are real light, extremely comfortable and have held up quite well for me.  

Approach shoes are another good recommendation along with Oboz.  

We typically average 12-15 miles a day once we get our trail legs, but I don't think I could go 20 miles in a day with my heavier Zamberlans or Danners.

ROCK6

I've had good luck Danners and more recently Columbia. A lot depends, as others have mentioned, on how heavy your pack is.  On my last trip, we hiked 7-10 miles a day for three days, my pack was just under 40 lbs.

Properly broken in is very important. I trust my life to these two:

American Made, Bates boots (they have/had the mil Gov contracts) good boots....I specified American made, because they have a line made in China (which are good, not great).

Redwing boots.

Danner 8" Rainforest, uninsulated.

Asolo FSN95s have been my go-to boots for several years.

What kind of terrain?  Is it a "walk" or a "hike"?  What are you carrying?

I found material longevity to be the merrel issue, not comfort.  I wouldn't let your shoe choice stop you from doing anything (those are fine until you find out they're not).  Just be more careful and allow more time to avoid the sometimes over-hyped ankle roll.

I wear the cheapest Keen mids any time I can help it and some old all leather Merrels if there's rain/dew.  I notice the comfort more than the ankle support.

The ventilators are ok, I have done the bug out drill /15 miles, obstacles and 40lb pack with no issue.  They fall apart within the year.  Sneaker boots are not worth your time with weight, the provide great veneration but no support.  I currently wear lowa.  On my second pair.  I have done carry the load in them for 3 years.  29 miles, 42 miles and 20 miles respectively in 20 hours with weight.  They are my go to boots.  Only drawback is the don't breathe as easy as others, but with a sock change every hour or so you won't have a problem.  I also found a good insole like the blue moldable sole brand really make a big difference.

Salomon xa pros

I'd have to go with my Merrell Yakota Mid Top boots or my Moab Ventilators. I wear Merrell's daily and have yet to completely wear a pair out.

I absolutely love my Keen Targhee II boots. Just bought another pair.

The current production Merrells are not made anywhere near as well as they once were. I hike a lot. I wear Merrell Moabs (or in the past chameleons) as my daily footwear because they are very comfortable. However, I stopped wearing Merrells on my hiking trips about 18 months ago. I switched over to Asolo Fugitive GTXs. My Asolos have at least 600 miles on them and they still have plenty of tread left and are for the most part still waterproof. The current production Merrells are simply not rugged enough for any prolonged heavy hiking use. In the year before I switched over to the Asolos I went through at least four pairs of Chameleons - all of them failed by coming apart at the seams.

eta: One of my hiking buddies switched over to Danners from Moabs recently and he seems to like them a lot - so that might be another option.

Keene.

No specific terrain in mind. Texas, I guess. Load would probably be light most of the time. I won't discount the possibility of a heavy load.

There were a lot of fantastic suggestions. I decided to try out a pair of the Vasque Breeze 2.0. They seemed well constructed, and I was able to try them on and walk around the store in them. REI was doing 25% off of them, so after the gift card I paid $63 for them. I have since walked the dog around the block (1 mile), and they are quite comfortable.

While there, I decided to try on a pair of Brooks Cascadia trail running shoes. I thought they felt pretty good. They are definitely on my to-buy-list now. I also tried on the Salomon XA 3D trail running shoes which were one of the first recommendations, I believe. I wasn't sure if they just didn't fit my foot right, but I was very conscious of where the sole was making contact along my arch. The Brooks felt more neutral or like my foot lay flatter in the shoe.