I've always found all 3 positions very useful, depending on the output of the pickups.
As primarily a Strat player I've found the neck position of a Tele very similar to the neck position on a Strat.
*Throaty, honk, warm*
The middle position great for more rhythmic phrasing with similarities to the middle position of a dual humbucker guitar.
The bridge position can do so much. Roll the volume back and strum out some Peace, Love and Understanding. Crank it and ride the tone knob you get anything from Buchanan to Zeppelin. The other element beside the 2 knobs is where you pick.
*Crunch, clang, crisp*
If a Tele ever sounds strident its not the guitar's fault.
Neck: Smooth "woody" tone, approaches edge of SRV tone, but hums. Mostly unusable
Bridge: Sharp, twangy biting/tone, but also hums. See above
Middle: Moderately smooth with some twang, still has classic tele sound; works well in most situations. That's where my switch is 95% of the time.