First impressions: Lighter weight, more breathable.
Although the Nike Metcon 6 looks very similar to the Metcon 5, when you put them on you'll feel the difference. The Metcon 6 was designed to be the most breathable version yet. Without buying into the hype, it actually does feel notably cooler/more breathable on the foot. The mesh fabric is also more stretchy than the previous upper producing the feeling of a roomier toe-box and added flex.
The bottom line is that this fits similar to the Metcon 5 but the addition of the lightweight mesh upper makes this an enhanced version of the 5. If you liked the 5, you’ll love the Metcon 6.