I have created an account with Newsgator as a backup for the times when Bloglines is down. Though I have subscribed only to 23 feeds, creating them in Newsgator was pretty painful. I realise that it is not in the best interests of the online feed aggregators to provide a common format for exporting/importing one's feeds (since this would prevent lock-in and force them to compete solely on the strength of their implementations), but it sure would be a nice feature to have.
Newsgator looks OK, but not as good as Bloglines. The default option is to retain all feeds as unread; one has to manually mark them as read. The site was also a bit sluggish, but this could just be a temporary thing. Though the UI is pretty neat, Bloglines' feels cleaner.