It's really horses for courses, the newsgroups give you access to thousands of topics - not just gardening. Using a newsreader can also allow offline reading, saving on your on-line time for dial up users.

The advantage of the web based service is it is more intuitive, and requires very little setting up. GardenBanter brings together all the gardening groups, so it has advantages if all you are interested in gardening.

GardenBanter is a lot quicker than Google for the groups that it mirrors, with messages being distributed and received in seconds / minutes rather than hours.