I generally like to tune by ear and usually do so very quickly in the quiet at home but have found the electronic tuner very useful at noisy gigs where, with the background noise and fellow musicians also tuning and doing warm-up licks and so on, it can be difficult to hear to tune by ear.

For "proper" tuning, what Midchuck has said is absolutely true, some final tweaking will always be necessary as the guitar (or any fretted instrument for that matter) is out of necessity a compromise when it comes to tuning.

Peace

mcmoo