One of the issues I first had were some duplicate policies/modules/rules
This is because when I first started using CSA, I would modify the original rule instead of creating and modifying a copy. I then had to manually cleanup the old 5.1 rules that were remained after the upgrade
Of course you always what to take backup the database and export and polices you may have before the upgrade as well
I just completed an upgrade from v4.5 to v5.2, albeit with the assistance of two CCIE's from a Cisco Gold partner. Probably the most important issue I can point out is that there is a HUGE bug in v5.2 r203 that prevents many hosts from obtaining a DHCP lease during bootup. So if you use DHCP be sure to skip r203 and go right to r238 which came out at the beginning of November.
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...