Tuners are not equal. There is a definite difference in accuracy. Peterson has a good demo on their site. http://www.petersontuners.com/demos/sdemo/index.cfm
Granted, they are trying to sell their tuners with this demo, but I have heard the same dissonance that they are demonstrating with one acoustic guitar. Now extrapolate that out over two guitar players, one or two keyboard players, and a bass. Of course we can all hear when we are out of tune, but when we are trying to get in tune, accuracy counts. I use my Korg sometimes, but I prefer my Petersons. By using a high quality tuner, I am able to tune my bass at the beginning of the night, and check it at the start of each set. Both of the guitar players in my band use cheap tuners, and have to adjust their tuning several times each set. In my opinion, it's because they weren't in tune to start with. It doesn't matter how good your bass sounds, or how good your amp is, if you're not in tune, you sound like crap. IMHO, with as much time and money we spend obsessing about our sound, buying a cheapo tuner just doesn't make sense. It's kind of like buying a Ferrari, and putting plastic, fake chrome hubcaps on it. Accuracy does count, and the more players that are involved, the more important it is. But that's just me, I could be wrong.