I tried three native apps and had problems with all of them. I recently switched to ihackernews, and everything's been great. The hidden killer feature is that you can use browser-provided tabs.
Also, iHackerNews has links to 'viewtext' on the article, which works on about 75% of articles that I've tried, and saves a lot of badnwidth/cpu/ram.
The viewtext service is also incredibly awesome for printing out articles on paper -- I've found it to be much better than even the custom "print" versions of many articles, and certainly better than readability, etc.