We just went Production with 7.7 from 7.6.8. A couple things we did run into.
1. You cannot use use JROCKIT's jdk on Weblogic 10.3 to deploy. You need to ensure you use Suns' jdk. We had a lot of issues it worked in WL 9 but not 10. Could not deploy the help files. We ended up running with Sun's jdk
2. Applying Hot Fixes, use Sun's 32bit jdk even if your on a 64bit machine. Not sure how Windows behaves but we installed our client on Linux and had a lot of trouble installing with Sun 64bit.
3. The 7701 install for Linux is a little buggy, you will need to go under the covers to enable options on the Welcome screen and to get Managed Reporting Reporting. Support should have all the documentation from my cases so if you go now with 7701 that should not how to support the install. Otherwise wait till 7702 comes out.
4. Reporting Server - All though it supports SQL Server 2000, when you install Report Caster you need to install 2005 or up, so be prepared to upgrade any RC databases.
5. Migration tools worked well, had no issues there.
6. Code is a lot tighter, so review your code. We found procedures that failed cause we had a type or two in like XFOCU instead of XFOCUS. Good thing.
7. As far as new features, I really couldn't tell you.
WebFOCUS 8.1.05