How does sram apex double tap work?
 

Is it as simple as one tap in for going up and 2 taps in for going down? sounds easier and quicker than shimano. looking at a allez apex 20112.

Press it a little (til the first 'click') to shift up a gear, press a lot to shift down a gear. Reverse for the front shifter.

its very intuitive. i've had sram for about 9 months and love it!!

Agreed...

I hate how far I have to push it to down shift. Just nit picking though, I suppose.

My only beef is the front shifting. Always seems to either be balky, rubby, or throw the chain.

As for shifting, my mnemonic was "bigger push = bigger physical gear". No matter whether it's front or back, a bigger push of the level gets you more teeth.

Quite well, from what I hear.

Here's a short video of the internals.
http://www.youtube.com/watch?v=7csDTkZMYM4

It changes gears when you let go. If you let go after one click, it'll shift into a smaller cog (harder to pedal). If you let go after 2 or more clicks, it'll shift into a larger cog (easier to pedal); 2 clicks -> 1 gear easier, 3 clicks -> 2 cogs easier.