I hooked mine up yesterday.  Mostly happy but getting dropouts more than I care for.  
 
I think my buffer is set to 128 - not as low as I had with my RME.  But the Apollo has the Unison feature, where you can record directly through an amp sim or mic input.  That has close to zero latency.  
 
I am looking for any experience anyone has optimizing their setup for an Apollo
 
Thanks in advance.
Space

I use mine daily. I cant recall any optimizations off hand other than FireWire related configuration.
 
-Make sure you are using one of the recommended FW cards: 
https://help.uaudio.com/hc/en-us/articles/205927069-Apollo-FireWire-Windows-Compatibility-
 
-Make sure nothing else is connected to the FireWire interface.
-Make sure you are using FW800; Just for overhead's sake.
-In the FireWire setting in the console software, make sure you allot as much of the FW bandwidth available -while still leaving a little available, I think I use 95% (not at home, cant check)
 
I can track projects with just audio and no FX with a 32 MS latency set on the Apollo, although the number of tracks is low (cant remember numbers). Most of my full mixes with 70 tracks and tons of edits and takes and FX.... 1024 or 2048 is required.

I've had mine for just over a year and a half now and it's working great although I was having issues with it a couple of weeks ago. The tech support guy at Sweetwater remoted into my system and did some tweaks to it and all has been smooth since then (knock on wood).
 
 Currently my buffer size is set at 128 for recording. I typically change this to at least 512 when I'm mixing. also the Firewire band width is set at around 65-70. This is one of the parameters that the tech guy tweaked for me.
 
You can probably get your latency down even more if you disable ALL UAD plugins except the ones you're tracking with during recording.
 
HTH!!!