Looking for an honest Nike Men's Flex 2021 RN Running Shoes Black White Smoke Grey Size 9.5 NIB vs Avia Hypersonic Gel comparison in 2026? We scored both running shoes on the same six-dimension framework — performance, battery, display, camera, design and value — using identical methodology, so the numbers below are directly comparable. Both products score nearly identically (60/100 vs 61/100) — this is a genuine toss-up that hinges on which specs matter most for your use case. On price the Avia Hypersonic Gel undercuts the Nike Men's Flex 2021 RN Running Shoes Black White Smoke Grey Size 9.5 NIB by 141% ($26.95 vs $64.99), which materially changes the value calculus for budget-conscious buyers.
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$65
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Nike Men's Flex 2021 RN Running Shoes Black White Smoke Grey Size 9.5 NIB and Avia Hypersonic Gel are closely matched running shoes devices with nearly identical overall scores (60 vs 61). The best choice depends on which specific features matter most to you.
✗ Cons
✓ Pros
| Spec | Nike Men's Flex 2021 RN Running Shoes Black White Smoke Grey Size 9.5 NIB | Avia Hypersonic Gel |
|---|---|---|
| Price | 64.99$ | 26.95$✓ |
| Weight | 310g | 300g✓ |
| Colors | Black, White, Smoke Grey | Blue, Green |
Buy Nike Men's Flex 2021 RN Running Shoes Black White Smoke Grey Size 9.5 NIB if…
The Nike Men's Flex 2021 RN Running Shoes Black White Smoke Grey Size 9.5 NIB is worth considering if you prefer its specific design, ecosystem, or brand — though it scores lower overall in our comparison.
Buy Avia Hypersonic Gel if…
The Avia Hypersonic Gel is worth considering if you prefer its specific design, ecosystem, or brand — though it scores lower overall in our comparison.
Nike Men's Flex 2021 RN Running Shoes Black White Smoke Grey Size 9.5 NIB and Avia Hypersonic Gel are closely matched running shoes devices with nearly identical overall scores (60 vs 61). The best choice depends on which specific features matter most to you.
Both products score similarly — it depends on your priorities.
Avia Hypersonic Gel is cheaper at $26.95 vs $64.99 for the Nike Men's Flex 2021 RN Running Shoes Black White Smoke Grey Size 9.5 NIB.
The Nike Men's Flex 2021 RN Running Shoes Black White Smoke Grey Size 9.5 NIB is worth considering if you prefer its specific design, ecosystem, or brand — though it scores lower overall in our comparison.
The Avia Hypersonic Gel is worth considering if you prefer its specific design, ecosystem, or brand — though it scores lower overall in our comparison.
Avia Hypersonic Gel is lighter at 300g vs 310g.
Reviewed by VersusMatrix Editorial Team
Last updated: May 31, 2026
Methodology: AI-powered analysis of technical specifications from manufacturer data. Scores are calculated by comparing products across multiple dimensions and normalized relative to the full category database. Our editorial process is independent and not influenced by affiliate partnerships.
Scores are relative within the running shoescategory. Percentages show each dimension's weight in the overall score. A difference of less than 0.5 points is considered a tie.