As Ceilidh Higgins puts it:
Whilst groups are error prone and seem to have a lot of bugs ... they are still the best available solution within revit for collecting together repetitive sets of objects.
She recently presented at RTC on this subject, and she has provided the associated presentation slides for download and viewing.
Get your groupon! A guide to Revit groups | The Midnight Lunch
You may also be interested in this AU class by Aaron Maller:
Autodesk® Revit® Links, Groups, and Documentation: How to Make It Really Work!