Had no problems nine days ago moving from Ubuntu 8 x64 6.0.10 to Ubuntu 8 x64 7.1.1. Upgrade script ran quickly as well.
With 6.0.10 and all previous versions back to v4, my average load usually was around 0.4 to 0.5. Now, my average load is under 0.1. Not sure what changed but I like it.