This depends entirely on how you'll use your Apple Watch since not every band is perfect for every situation. For instance, if you work out a lot, you probably don't want to buy a leather strap as your daily driver. Some straps and materials are more versatile than others and can be used in a variety of different ways. For example, a woven nylon band is a great workout strap that can also look good in an office setting. Classifying any Apple Watch Series 9 band as the ultimate best really just comes down to how it's used.