I’ll start off with a warning.  I’ve been running 8.3.1 on my home 5505 for a few hours now.  Not only is this not really enough time for a thorough review, it’s also not the environment to test enterprise-level configurations.  There are also a lot of details missing that I just don’t know about yet, so please do some research on your own to figure out what’s going to break if you upgrade your ASA.