Here's the iOS wiki. Scroll down towards the bottom (just above the Apple TV section) and you'll see the 4.3.2 changes. Now I'm not sure if it's an improvement on how long the battery lasts or if it helps the accuracy of the battery meter.
http://en.wikipedia.org/wiki/IOS_version_history
The battery improvement isn't in any official change logs so I can't say with complete certainty that things are better. I have to wait and see how my usage goes and tell from that. I can say the animations on my phone are improved. Things seem to open and close with a more fluid motion compared to how 4.3.1 was on my phone.
http://www.gottabemobile.com/2011/04/15/ios-4-3-2-update-seems-to-have-improved-battery-life-reporting/
Starting at the sixth post down in this thread you start to hear mixed reviews about it helping and hurting battery life.
https://discussions.apple.com/thread/2815566?start=15&tstart=0
So far my phone percentage isn't going down as fast as it was before. For me it's been an improvement...so far. It's still too early to say for sure but it's promising.