Merrell Agility Peak 4 vs Merrell MTL Long Sky: which should you buy?

The Merrell Agility Peak 4 is built for longer distances. Merrell MTL Long Sky is for lighter work. Which is right for YOU?

Merrell Agility Peak 4 vs Merrell MTL Long Sky
(Image credit: Merrell)

Merrell Agility Peak 4 versus Merrell MTL Long Sky: it's the showdown you've been waiting for. If you are a fan of Merrell trail running shoes, and enjoy conflict.

Merrell is all about the trail running shoes, and is also known for making some of its kicks vegan friendly. But beyond thinking about your impact this purchase makes on the planet, it's important to think about the impact these shoes will have on your precious feet. 

In our Merrell Agility Peak 4 review, I praised these cutting-edge trainers, which are full of tech to make sure your feet get the best protection and grip while on those longer trail runs. They still look good enough to take on the roads but offer a sole which can withstand even the more brutal stone-filled paths.

Standing at the other end of the range, in many ways, is the Merrell MTL Long Sky. This is a lighter shoes that's built for the trail, so you do get protection, but it's more about giving you feedback on your run. That said, this still offers a strong sole and expansive lugs, only this also offers light pronational control for those that need it.

So if you're looking for the best trail running shoe, and have an eye on your environmental impact, a Merrell option could be right for you. NB: if you prefer to hit the road, we also have a guide to the best running shoes for less rural settings.

Merrell Agility Peak 4 vs Merrell MTL Long Sky: the tech

Merrell Agility Peak 4

Merrell Agility Peak 4 is a big-heeled, tech-packed shoe

(Image credit: Merrell)

Both of these trail runners pack the MegaGrip sole from Vibram meaning big lugs with plenty of grip for wet rocks as well as loose gravel paths. The big difference in the two is the heel drop with a high 8mm on the MTL Long Sky and a lower than average 6mm on the Agility Peak 4.

What does that mean for you? On paper it could mean the Agility shoe has less heel support, but thanks to a smart FloatPro midsole, this actually offers plenty of support. That said, for literal foot envelopment the MTL does feel like your heel has more material around it.

The upper is also very different with the MTL offering a heavily padded shoe which is great for colder conditions but can get a bit overheated in warmer climes. The Agility Peak 4 uses a Jacquard upper with integrated lacing system which remains breathable yet warm enough and also clings tightly to the foot for an envelopment which aids responsiveness the of this shoe.

Merrell MTL Long Sky

Merrell MTL Long Sky is less sophisticated and more cushioned

(Image credit: Merrell)

Merrell Agility Peak 4 vs Merrell MTL Long Sky: performance

Merrell versus Merrell

(Image credit: Merrell)

For all out trail performance the Agility Peak 4 packs in all the latest tech and offer a balance between impact absorption, thanks to that sole, and feedback, from the smart fitting upper. The flex of the midsole also plays a big part here which results in an ability to cut across steep inclines without too much torsion but while having enough flex to feel free.

The MTL Long Sky, by comparison, is a lot more cushioned, making it great for a comfy flat trail but likely a little tough on the joints for anyone taking on lots of hills too. This is the lighter of the two, which makes it great for a quick trip out and back. But for those longer trails it's the Agility Peak 4 that you'll want to lace up.

Merrell Agility Peak 4 vs Merrell MTL Long Sky: Ergonomics

The lightweight EVA foam inner featured in the Agility Peak 4 shoes does offer a lot of comfort while keeping breathable and light. The inner is removable which is ideal if you're using these for longer runs and want to wash them, but equally if you head into a lot of wet and want to dry them faster.

The heel difference is a big feel factor here. Go for the Peak 4 if you want freedom in the back that gives a great foot roll, but if it's all out heel support that gives you confidence then the MTL Long Sky is the winner. You also get that slight pronation support in this shoe which can be a big appeal for many runners.

Merrell Agility Peak 4 vs Merrell MTL Long Sky: aesthetics

Merrell has a very distinct look, one that comes through in both of these shoes. At first glance they have a lot of sole height, a dizzying amount, perhaps. But on closer inspection that works into the upper of the shoe, in the case of the Agility Peak 4, seamlessly and actually enhances the look of these bright shoes.

The MTL Long Sky has a more padded upper finish which can give it an older style appearance. Both feature over lacing systems which makes for a tight fit but this look isn't for everyone. What this does have is a large branding mark which doubles as a reflector, helping visibility on night runs.

Merrell Agility Peak 4 vs Merrell MTL Long Sky: verdict

The Merrell Agility Peak 4 shoes are impressive for their, often reduced, price. You get a light layer that fits well, is breathable and offers plenty of sole cushioning and enough heel and midsole support to get a consistent pace naturally. These are built tough to go the distance of even ultra trails.

For a quicker trip out, more on the flats, it's the Merrell MTL Long Sky that offers a lot with that full bodied build and slight pronation support. These are for anyone that feels the cold in their feet and wants cushion comfort on the top while still getting the protection and grip from that Vibram sole.

Luke Edwards
Luke Edwards

Luke is a freelance writer and editor with over two decades of experience covering tech, science and health. Among many others he writes across Future titles covering health tech, software and apps, VPNs, TV, audio, smart home, antivirus, broadband, smartphones, cars and plenty more. He also likes to climb mountains, swim outside and contort his body into silly positions while breathing as calmly as possible.