There is a consensus that index cards are the best tool for grooming user stories. Index cards are physical, they encourage participation and are easy to handle, store and update. Index cards are good but there are situations when their usage can introduce problems. I will here address three of them.
First, if an agile team contains remote members physical index cards are pretty useless to the remote person. Then an electronic system would be better. Some use shared spreadsheets some use a specific program like ScrumWorks or JIRA. The idea is of course to provide the same information to the remote team members that is available to people present in the grooming.
Secondly and a much more common issue is when the groomed items requires lots of detailed information, for example, when grooming a particularly nasty defect in your overly complicated system. You just can’t fit the logs on a single index card, right? You really need the full email correspondence!
Thirdly, people might be reluctant to use index cards because it is secretary work. That is, they don’t like the idea of writing a lot.
I can understand and support the first issue and its solution but I disagree with the second and third issues.
You don’t have to put all relevant data into an index card. You need only the high level story, acceptance criteria and/or story tests and a small space for the estimate. Everything else can remain in whatever electronic tracker you are using.
For the reluctance of writing in hand I would just emphasize the ease of participation with index cards. Anyone can grab one and add a note. Try to do the same with a laptop.
With index cards after the grooming someone will volunteer to insert the contents of the index cards into the tracker and you have had an enjoyable grooming session with people discussing actively and you have witnessed participation. No more neck-breaking peeks at the projection screen nor watching someone type the discussion as it happens.
If you are properly prepared for the grooming session index cards are a perfect tool for grooming. We humans like to touch physical things after all :-)