Fit Simplify is the overall winner for most people because it’s a widely adopted loop-band set with strong buyer sentiment, a solid quality profile, and good usefulness across strength accessories, stretching, and PT-style routines. Its main limitation is that rolling/bunching and durability over time are still mixed based on user reports.
COOBONS FITNESS is the better “budget + portability” pick, with excellent small-space practicality and clearly stated warranty/return details. Its main limitation is more variable feedback on durability and fit/staying in place. If you want the safest general choice, go Fit Simplify; if you want the cheapest set you’ll consistently use anywhere, COOBONS FITNESS is a sensible alternative.