I have always had the best luck with Korg tuners: inexpensive, accurate, stable. I started with a rack mount 20 years ago, which I finally gave to a friend of mine who runs a weekly open mike night at a local watering hole, then went to the hand-held, which I keep with my tuba because of its built in microphone, and now I'm using the headstock clip on model. I have used tuners ever since high school concert band, when my band director had an original Conn Strobo-Tuner. I've tried many different models over the years, including a Snark whch I have clipped to the bridge of my double bass, but I always come back to the Korg. If they cost double the price, I'd still get them.
The aspect that sets Korg apart from the Conns, the Petersons, and all the other great brands is their ability to filter out the overtones and read the true fundamental, which, of course, is especially necessary on bass, so that it actually tunes E1, for example, and doesn't try to tune E2, or B2, or any other overtone instead.