UPDATE: I came up with a customizable version of Recent comments widget later. Please try it instead of this.
The much-awaited comments feed is completely functional now! I saw Hoctro's post on this topic and found my blog's comments feed also working great. Blogger team seems to have fixed the stale comments issue on Friday. It's very easy to show recent comments in sidebar now (as I have done in my widebar - the wide sidebar). Just goto Page Elements tab, add a page element of type Feed to sidebar and give the following as the Feed URL.
http://yourblogname.blogspot.com/feeds/comments/default. You could select to show the date and comment author if you want.
Notice that they have changed the feed URL not to contain any blog ID etc. This makes it easy to play with any blog's post and comment feed URL programmatically.
UPDATE: Many readers asked me why comments are not immediately shown after published. It is because it takes some time for the new comments to be added to the comment feed. Just wait for some time and it will show up. Yes, this is a limitation of using feed to show recent comments.