Please consider adding a screenshot of the iPhone Comments view to either your site or the App Store listing. The Comments interface would be the deciding factor for me - I still haven't found a HN app that gets this right.
The comments UI is the deciding factor for me as well. So far, the best implementation of this I have come across is cheeaun's Hacker News mobile web app: http://cheeaun.github.com/hnmobile/landing/
I'd also like to request this, comments are a big factor of HN for me. I'll definitely be buying either way it's a lot nicer interface than a few I've seen.
Please consider adding a screenshot of the iPhone Comments view to either your site or the App Store listing. The Comments interface would be the deciding factor for me - I still haven't found a HN app that gets this right.