Reeder is the best one I think too. It's interface is great and it's iPhone app is amazing. Bad news is you get hit twice on iOS. No universal app.
The best thing about all the OSX/iOS apps is the readability integration. If you hit the readability view, the whole article is downloaded and presented in a Safari reader type view. This is particularly helpful for feeds that annoyingly don't give the full article in the feed, i.e. The Economist, and also for ad-ridden pages.
Ability to send articles to Instapaper and other similar services is also fantastic.
Two things to note however, (1) Reeder is not a repository for all your feeds. You need to use Google Reader and Reeder just logs into Google Reader. (2) The current version in the app store is reported to have a memory leak. I never leave Reeder open that long as I mostly use it to send articles to Instapaper so I haven't experienced that problem.