The Your subscriptions tab is very slow when you have hundreds of subscriptions like myself. Patience is a necessity.
OPML item use title attribute instead of the text attribute. A very common mistake. The outline is missing the htmlUrl attribute (consider that a feature request). The OPML head is empty; it would be nice to see <title>Reading list from Google Reader</title> or something like that.
I like the Starred items feature. Basically, I read a few hundred items and star the ones I need to take action on. It's the same behavior I've taught myself reading email in Gmail.
Gmail this is pretty cool too! Mail this using the mailto URI scheme would have been more karma centric.
I wonder how the <item> relevance is calculated?
The IE process for Google Reader is over 133M as I type this.