Dave Potter I use the above approach, works great. I have a query to return all products created past 30 days, and modified past 30 days, and sort/filter by user or any other field, exporting the item list to Excel if needed.

Note that Modified By only returns the single user that last modified the item, not a list of all users that modified it within a time frame. I really only use it to see anything that's hot for example if there are tons of bulk edits, just to make sure nothing crazy is happening with the catalog.