The Best and Worst Surprise Running Shoes of 2021: Six Hits and Two Misses

Introduction

2021 was a relentless year for running shoe releases. Some launches arrived with enormous hype and still managed to disappoint, while others were barely on anyone’s radar and turned out to be genuine standouts. This roundup pulls together the shoes that surprised for the right reasons and the ones that missed the mark, so you can spend your money on the former and skip the latter.

The Best Surprise: Adidas Prime X

The Prime X was easily dismissed as a novelty before release: a huge stack of cushioning with a hefty price tag that looked more gimmick than serious trainer. In practice, it turned out to be one of the favorites of the year. The massive Lightstrike Pro midsole delivers outstanding shock absorption, which makes it a genuinely helpful shoe for runners coming back from injury or simply getting out the door on low-motivation days.

The upper is odd-fitting but functional, the pliable rubber outsole offers superb grip, and the energy rods and blade construction embedded in the midsole give the shoe a lively, forward-rolling feel. Aside from uneven ground, it is a real road running winner, and probably the most surprising shoe of the entire year.

The Everyday Surprise: Nike Pegasus Trail 3

Picked up on a whim, the Pegasus Trail 3 ended up being one of the most-reached-for shoes in recent memory. The React midsole is notably softer and more forgiving than much of what Nike has released in recent years, and it works beautifully for both walking and running.

It also gets the details right: a wonderfully roomy upper, protective elements in the toe box and on the outsole, and reasonable lug depth that keeps it feeling natural on road sections. It is not a technical trail shoe, and other models handle that terrain far better, but for all-round use in comfort and durability terms it is hard to beat. If you want a winterized option, the Gore-Tex version is worth a look too.

The Sleeper Race Shoe: Asics Meta Speed Sky

The Meta Speed Sky is another shoe that could easily have been slept on all year. It is incredibly light with a huge amount of rebound, and it firmly puts Asics back in the race shoe conversation.

The one question hanging over it is whether a future version with more foam will actually be better, a debate that applies across the whole super-shoe category. Either way, the FF Blast Turbo foam here deserves more attention in 2022, and this shoe is well worth considering if you want a lightweight race day option.

The Biggest Disappointment: Adidas Boston 10

Not every surprise was a good one. The Boston 10 comes in 75 grams heavier than the Boston 9 in the tested size, and the combination of rods and plates feels clunky rather than quick. Even a half size up from the usual fit, the upper is restrictive over the top of the foot, almost like running with ankle weights.

The Boston 9 was a beautiful shoe that simply sat on foot and sung every time it hit the floor. The Boston 10 feels like technology shoehorned into a chassis that does not suit it: too much upper, a plate in the heel that adds little, and an overall uninspiring ride. If it works for you, great, but the hope is that Adidas returns to the classic Boston formula in future versions.

One Still Under Review: Adidas Takumi Sen 8

The Takumi Sen 8 sits in a holding pattern. After limited miles, the shoe is beginning to flex a little more and is starting to feel more like a proper racing flat. Whether there is a genuinely great shoe hiding inside it remains to be seen, and it deserves more miles before a final verdict. Consider this one a wait-and-see rather than an outright recommendation.

The Pleasant Surprise: Under Armour Flow Velociti Wind

The Flow Velociti Wind is another shoe that delivered more than expected. It is light, and the new Flow midsole material really is something: responsive yet still forgiving, comfortable even at around 14 miles.

The upper is the other highlight. It is airy and thin, yet still provides pleasing lockdown over the top of the foot. This is a shoe with real potential, and its development in 2022 is worth watching.

The Letdown: Nike Zoom Fly 4

The Zoom Fly 4 is the final disappointment on the list. The prominent arch and oversized upper show very little development over the Zoom Fly 3, which launched years earlier. With so many other manufacturers pushing far more advanced implementations of foams and plates, the Zoom Fly 4 feels outdated rather than refined.

It is telling that the next version, the Zoom Fly 5, appears to be a total reimagining of the model. If the Zoom Fly 4 works for you, great, but there are stronger options at this level.

The Verdict: Which 2021 Surprises Are Worth Your Money

If you want maximum cushioning for easy days and recovery runs, the Prime X is the standout surprise of the year. For an all-round trainer that doubles as a comfortable trail shoe, the Pegasus Trail 3 is the most usable pick here. For race day, the Meta Speed Sky is the exciting lightweight option, while the Flow Velociti Wind is a solid tempo choice with an impressive new midsole.

On the other side, skip the Boston 10 unless the classic Boston formula has already worked for you in the past, and think hard before choosing the Zoom Fly 4 over newer alternatives. The Takumi Sen 8 is best left on the bench until more miles confirm whether a great racing shoe is hiding inside.

Conclusion

2021 proved that hype and quality do not always go hand in hand. The Prime X, Pegasus Trail 3, Meta Speed Sky, and Flow Velociti Wind all overdelivered, while the Boston 10 and Zoom Fly 4 remind us that a familiar name is no guarantee of a great ride. Match the shoe to your actual running needs and the surprises mostly fall in your favor.