On the one hand, performance and responsiveness are better than previous ROM updates, and I've consistently had an extra signal bar everywhere I've been (Pittsburgh area and Youngstown area). I have run into no compatibility issues with any of the apps I use (I'll list them below), and I'm still hovering at the 10-15MB of RAM free.
On the other hand, under 3.35, I was able to take my phone off the charger at 7:20am every morning on my way out the door to work and put it back on the charger around 11:00pm as I went to bed. Doing this I would drop to approximately 60% battery life.
Since updating to 3.56, I am like many others having a faster battery drain. Specifically, today I took it off the charger at 10:00am and it's 9:00pm but I'm down to 42%. I am using an identical setup including the same registry tweaks and program installs, and usage is about the same as any other day (ie. a few 5 minute calls, a handful of web pages and text messages, and email syncs set at 60 minutes).
That said, I would prefer to have better battery life, so if it doesn't miraculously improve over the next couple days or unless HTC releases a slightly newer build tomorrow, I'll be reverting back to 3.35.
Incidentally, here's the list of apps installed that I can confirm are working as expected:
acbToggleBT
Google Maps
HTC Comm Manager (6-button, updated based on 3.56 files)
HTC Touch Dialer
Microsoft .NET Compact Framework 3.5
no2chem Battery.dll, nueAudio, nueExtRom, and nueFonts
Palringo
PCM Keyboard .14
PHM RegEdit
Remote Desktop 6.1
S2U2 1.05
SipChange
SKTools
sMMS
Spb Mobile Shell 2.1, Phone Suite 1.3, and Pocket Plus 4.0.2
Spb Watcher
Sprint TV
Windows Live Mobile
Windows Live Search
YouTube Player