I've only used it once. It's a little tricky to use the first time, but once you figure it out it's amazing. The whole process could be improved with a better instructional video. The instructional video should be one continuous video to show the whole process and not broken up. Also, the list of pins and derailuers needs to be updated. Customer service is great and very responsive. I wasn't sure which pin to use and emailed the company. I got a response within a couple hours with more specific instructions for my derailuer.