I have used electronic tuners for years and wouldn't do without one. My ear is much better on account of it too, because now I'm more used to proper pitches and my ear is less tolerant of bad tuning.
Currently I'm using a Yamaha tuner which sits on my music stand and I carry it everywhere. I'd like to get the better Boss tuner with the needle because it's more visible in outdoor venues (which ruin the use of LED units, btw). My live rig has a Danelectro floor pedal tuner wired so I can use it for every guitar without plugging out and plugging in all the time.
Obviously I'm sold on the value of a good tuner, but maybe the best part is the time saved when jamming/practicing with others. I wish I could pursuade all my students to get one.