dstrenz
I always have a bit of trouble tuning the low E on basses with any tuner unless the strings are brand new. Hitting either the octave harmonic or the x2 harmonic on the 5th fret helps.
This is where the iPhone TC Polytune app really shines.
Tracks low notes super smooth... no jumping around
When the sub cabs are cranking, all of my clip-on tuners have issues (Snark, Korg, etc).
For pedals, I like the HardWire HT-6 polyphonic tuner better than the TC Polytune.
It's a bit more stable and easier to see on a dark stage.
Ironically, I find the Android version of the HT-6 app all but useless (jumps around constantly).
The polyphonic tuner in the Boss GT-100 is also very nice.