I installed different Hipshot D-tuners on 3 of my Fender basses. They are amazing. Hipshot has a video on Youtube about how to set these up correctly, go watch it! Be sure to check the main screw from time to time, to see if the string is still in tune when downtuning. You can put a tiny bit of Threadlocker to prevent movement on this screw too.
Only cons would be the price, I hope these get cheaper over time.