On Cloudboom Max vs ASICS Megablast: Which Marathon Shoe Deserves Your Money?

Introduction

Marathon shoes have quietly split into two camps. On one side sit the elite-focused super shoes, and on the other sit shoes built for the vast majority of runners chasing a solid finish rather than a podium. The On Cloudboom Max and ASICS Megablast both live in that second space, and both carry premium price tags, which makes choosing between them genuinely difficult.

After spending serious mileage in both, the picture that emerges is less a head-to-head of equals and more a case of one shoe doing a very specific job and the other being far more versatile.

The Contenders at a Glance

The ASICS Megablast costs £210 or $225, weighs 225g or 7.9 oz for men in a size 8, and has an 8mm drop. It is the new super trainer in the line, following the popular Superb Blast and Super Blast 2, and is designed to deliver a lightweight, responsive ride across a range of sessions with more versatility than its older siblings.

The On Cloudboom Max costs £220 or $230, weighs 283g or 10 oz for men in a size 8, and also has an 8mm drop. It is designed for marathon runners of all levels, with a particular focus on those targeting a four-hour finish.

Both shoes sit at the expensive end of the market, so the question is not just which feels better, but which one justifies the outlay for the way you actually run.

On Cloudboom Max: Built for a Very Specific Job

The Cloudboom Max uses a dual-layer Helion HF Hyperoam midsole for improved energy and comfort, along with more support and cushioning than many elite-focused super shoes. There is a plate running through the shoe, a glass fibre infused speedboard, and updated geometry aimed at improving efficiency for runners targeting a four to four-and-a-half hour marathon. The upper is a light, breathable mesh that adjusts to your foot over long distances, and the outsole offers generous rubber coverage for grip and midsole protection.

In use, the shoe ticks a lot of boxes. The main benefit for four-hour marathon runners is stability: you get a little more support while you are out there, and the firmer, denser midsole foam makes it a strong option for heavier runners who want more structure holding them up. It is comfortable, smooth, and well suited to long distances at a consistent pace.

The catch is that it does not feel like a fast shoe. At around five minutes 20 per kilometre, roughly four-hour marathon pace, it works fine, but it does not feel like it is doing much above and beyond a good comfortable everyday trainer. It feels relatively heavy on the feet and is more conducive to steady, consistent running than to picking up the pace. If you judge it as a super trainer, it is a solid shoe. If you judge it as a race shoe with a specific finish-time target, the case is harder to make at this price.

ASICS Megablast: The More Versatile Ride

The Megablast is built around an FF Turbo Squared midsole that balances a cushioned, smooth ride with a high level of energy return. The grip outsole is designed to enhance traction and control, supporting smooth acceleration and efficient energy use, while the engineered woven upper is lightweight and breathable enough to keep your feet cool when you pick up the pace.

On the road, it simply has more life in it. It feels lighter on the feet, bouncier, and smoother than the Cloudboom Max, with a lovely heel-to-toe transition. The midsole is softer, so it is not as stable, but it is well balanced and by no means squishy. It is not the fastest interval shoe out there, but it handles everything from easy runs to strong finishes, and it is considerably more versatile than the Super Blast.

It also proved itself over the full marathon distance. Running at five-minute to five-minute-20 pace, it stayed comfortable throughout, and it still felt great when the pace dropped to around four-minute kilometres in the closing stages. Even at the end of a marathon, there were no hot spots or discomfort, which is unusual for a shoe without a carbon plate.

Fit and Sizing: The Practical Deal-Breaker

The Cloudboom Max runs short. In a UK size 8, the big toe sits very close to the end of the shoe, which raises real concern over 26.2 miles of repeated toe contact. Sizing up half a size is the sensible move here. Otherwise, the fit is fine: the midfoot is fairly average in width, the forefoot space is good, and the padding around it makes for a comfortable wear.

The Megablast is the opposite. There is plenty of room before the big toe, lots of forefoot and midfoot space, and a generous padded heel collar that makes it a very comfortable shoe out of the box. Most runners can stay in their usual size, though anyone who prefers a snug fit might consider going down half a size.

On durability, both outsoles hold up well. The Cloudboom Max has a notably thick, sturdy rubber outsole with no signs of the wear that often plagues race shoes. The Megablast has slightly less coverage in places and a marginally more delicate midsole, but it still offers a good amount of rubber and solid grip.

Verdict and Buying Advice

These two are tricky to compare because there are not many true peers for the Cloudboom Max. You cannot match it against conventional carbon-plated race shoes, since those are designed for a very different purpose. Judged honestly, it behaves more like a super trainer: some performance benefits, but oriented toward consistent pace, support, and durability. Its real advantages over the Megablast are stability and sturdiness.

The Megablast, however, is the better all-round shoe. It feels lighter, bouncier, smoother, and more natural, it is more versatile across training and racing, it proved outstandingly comfortable over a full marathon, and it is cheaper than a shoe that is already one of the most expensive trainers on the market. For racing, training, or easy runs, it is the stronger pick. Choose the Cloudboom Max only if stability and a firmer, more supportive platform are your absolute priority, and you are committed to the On fit and feel.

Conclusion

The ASICS Megablast wins this comparison comfortably. It costs less, feels livelier, handles more types of running, and delivered a genuinely comfortable marathon experience from start to finish. The On Cloudboom Max is a well-built, stable, durable shoe, but its specificity, higher price, and heavier ride make it harder to recommend for most runners. If you are targeting a four-hour marathon or simply want one shoe that can do a bit of everything well, the Megablast is the one to buy.