I used a Boss TU-2H for close to 30 years before it slowly disintegrated over the last 2 years. Was a fine tool for a long time.
I replaced it with a Peterson Stomp Classic that I bought last summer. This tuner is ridiculously fast, and easy to use/read. I like this a lot. It will mute when you stomp on it, and this is extremely useful if you have any instruments that need frequent tuning. It's a snap with the Stomp Classic, and the rest of the band isn't left waiting for you. It's also built like a tank, of heavy metal, and may be used as a boat anchor or a weapon in a pinch. It is unquestionably the Best Pedal Tuner for Metal.
For my acoustic instruments, each case gets an Intellitouch PT-10. Accept no substitutes.