If you are serious about looking after your instrument, keeping it in tune should be on your 'must do' list. To many of us, keeping in tune simply means getting it to sound right, maybe we have a song reference for this. However, the human ears are rather averse to the broad sound frequencies in general, less those virtuoso pros who are endowed with perfect pitch. All this boils down to having a reliable tuner to keep our tuning in check. There's so much a clip-on tuner could do due to its vibration detection capability, I'd always tell friends to invest in a reputable pedal tuner because a plug-in tuner is more accurate in this aspect (not relying on vibrations).
My pleasant encounter with good pedal tuners started with the Korg Pitch Black series & that was pretty much a bench mark for me when evaluating others of similar functionality. Today, Korg has 3 variants in its PB tuner range as seen above: 1) PB Standard 2) PB Polyphonic 3) PB Custom.
Because I believe in what the PB tuners have to offer in terms of features & durability, I bought myself this Custom version which is essentially a strobe tuner. Strobe type tuners are the best when it comes to intonation (tuning vs intonation- know the difference). If you think your off-the-shelf instruments are spot on with open tunings, wait till you check the intonation at the upper frets. Anyway, the Korg PB series of tuners are my recommendations to you if you wish for a value-for-money pedal unit which aren't costly.