These are a great option for gym flooring. There was a time, these were the only good option. Great way to protect your concrete floors from cracking - I hope. They are heavy, low cost, unless you have to buy a ton of them. They are a pain to move, a pain to cut, but they work perfectly. They smell at first, but the smell eventually completely dissipates - over a few months. There are many alternative options nowadays. Though, I cringe at the idea of having to replace them for new flooring. The juice doesn't seem worth the squeeze, given that horse stall mats are perfect as is. Only issue is they tend to change in pattern if not purchased all at once. My gym has been evolving over the years - as many others, I'm sure.
Performance
Value
Build Quality