I ran 40 miles with the Cloudsurfer 2 vs. On Cloudmonster 2 — which shoe should you buy?

Tom's Guide

14-06-2025

The On Cloudmonster 2 is a cushioned daily trainer that's a little firmer than most running shoes these days, including the Cloudsurfer 2. It's a good option for long runs, and despite being heavier than the Cloudsurfer 2, it's more responsive and similarly versatile.
The On Cloudsurfer 2 is a comfortable daily trainer with a smooth, rockered ride. It's softer than the Cloudmonster 2, as well as being lighter and cheaper, but it's not the most durable shoe and also feels a bit flat on longer runs or when running at faster paces.
The On Cloudsurfer 2 and On Cloudmonster 2 are both comfortable running shoes that are great for daily training, but they have different feels on the run that may make them suitable for different kinds of runners.
I've done around 40 miles of running in each shoe, and below you'll find my direct comparison of their relative strengths and weaknesses. Check out our On Cloudmonster 2 review and On Cloudsurfer 2 review for a more detailed take on each shoe.
The On Cloudmonster 2 is the more expensive of the two shoes, costing $180 / £170 compared to $160 / £150 for the On Cloudsurfer 2. However, the Cloudmonster 2 is also the older of the two shoes, so it's a little more likely to feature in sales — it's currently in the On last season sale for $140, so it's worth checking when comparing the two shoes.
The On Cloudmonster 2 is currently available in 11 colors, while the Cloudsurfer 2 is currently available in five colors.
At 10.7oz for a US men's size 9.5, the Cloudmonster 2 is the heavier shoe, with the Cloudsurfer 2 tipping the scales at 9.7oz in the same size.
Part of that weight difference is down to the fact that the Cloudmonster 2 has a higher stack of foam in its midsole and a lower drop with a 6mm heel-to-toe offset — the Cloudsurfer 2 has a 9mm drop.
I found that both shoes fit me well enough in my normal running shoe size, but as someone with a narrow foot, the Cloudmonster 2 did feel very wide and roomy in the toe-box — I preferred the snugger fit of the Cloudsurfer 2.
The Cloudsurfer 2's upper is thicker and more padded around the tongue and collar, with the Cloudmonster 2 using a more breathable material and a thinner tongue.
Both uppers flex well and support the foot securely around the midfoot and heel, but the Cloudmonster 2's upper might feel less oppressive if you're always running in hot conditions.
By far the biggest difference in the design of the two shoes is how their midsoles are set up. The Cloudsurfer 2 uses On's soft Helion foam with a series of holes designed to collapse like dominoes and create a rockered feel to the ride.
This CloudTecPhase design makes the ride smoother than that of the Cloudmonster 2, which has three layers of foam in its midsole.
The Cloudmonster 2 uses Helion foam for its top layer, and then the bottom is On's distinctive CloudTec pods, which are made from a firmer and heavier material than Helion.
There is also a nylon-blended plate, "Speedboard," in the midsole of the Cloudmonster 2, which helps stabilize the high stack of foam and speed up the transition from heel to toe.
Both shoes have pods on the outsole of the shoe, with rubber covering the forefoot and heel, leaving some exposed foam in the midsole.
I didn't notice a difference in the grip of the two shoes, which have both delivered reliable traction in the wet, and neither outsole is showing any undue signs of wear and tear after around 40 miles of running.
I used both the On Cloudsurfer 2 and On Cloudmonster 2 for a variety of training runs, mostly at an easy pace, with some faster intervals thrown in.
In my testing, I found that both shoes excelled in similar runs and had the same weaknesses — both are good for easy runs and neither feels that responsive at pace, but they have quite different ride feels.
The On Cloudsurfer 2 is a lot softer than the Cloudmonster 2, and the rocker is very noticeable on the run. It has a smooth feel that feels great for ticking over at a relaxed pace.
At faster paces, I found that the soft foam flattened out and the shoe didn't give a lot back in terms of energy return. It's quite a light shoe and you can run quickly in it, but it doesn't feel as good as it does for easy runs.
In contrast, the Cloudmonster 2 has a firmer ride and doesn't roll through as smoothly, but the midsole setup is a bit more responsive and bouncy.
I found the Cloudmonster 2 better for long runs than the Cloudsurfer 2, and although it's heavier, it was as good for faster runs as the Cloudsurfer 2 because the midsole foam provides more energy return.
Overall, neither are shoes I'd describe as exceptionally versatile, but both are good daily trainers that work well for easy runs and can handle speedwork reasonably well.
I'd pair either with a lighter shoe for fast runs myself, but if you want one shoe for everything, both can do the job.
My preferences skew towards lighter and rockered running shoes, so I'd reach for the On Cloudsurfer 2 myself. I found it more fun to run in, and it was easy to get into a good rhythm on easy runs thanks to the rockered midsole.
It's also cheaper and lighter, and the fit is a little better for me because I have a narrow foot. I love the look of the Cloudsurfer 2 as a casual shoe, too.
The On Cloudmonster 2 has its strengths, though. I think it will be more durable thanks to its firmer midsole foam, and it holds up better on long runs when the Cloudsurfer 2 can start to feel a little flat. It also feels more natural when walking than the softer Cloudsurfer 2.