Oukakimono really knows what they're doing when it comes to kimono rentals - speaking from experience, this is a solid choice with locations in all the major tourist cities. Just make sure you're season-savvy with your choices (we learned the hard way that wearing a winter kimono in summer is like walking around in a portable sauna!).
What makes them great is how they've got the whole experience down to a science - from helping you choose the right style to making sure everything fits perfectly. They understand tourists' needs with their multilingual staff, but they don't compromise on authenticity.
Pro tip: While they have locations in Kyoto, Osaka, and Tokyo, their Kyoto operation seems particularly well-oiled - makes sense since that's where most people want to do their kimono photos. The staff really takes time to help you coordinate all the little details that make the difference between looking like you're wearing a costume and looking properly dressed.