You may find the following helpful in your testing process.
Is is essential that we need to test out the new high performance event handlers for accuracy - the logic in the code is completely different and we want to make sure it is completely correct. You can help this by comparing the old and the new code - the beta version of the code provides a useful tool for doing this (which will be removed in the release code!).
When you are viewing a calendar (monthly, yearly etc) you can revert to the old code by adding a "&nv=0" ("?nv=0" if you are using SEF) to the URL. If you use a modern tabbed browser (like Firefox, Opera, Safari, Konqueror or MSIE 7beta) you can view the two versions in adjacent tabs and by toggling to and fro between them you should be able to quickly see if the event layout is the same.
Please let us know how you get on with this exercise.