The apps normally make reading comments much more difficult by a) enforcing a very large font size and/or b) only showing a single level of comments at a time. AFAIK news:yc does both of these things.

news:yc has a small text font setting and a nested comments setting which shows all comments rather than just one level at a time.

Awesome! When it first came out it certainly did not ;P. (The main developer works with me on Cydia, and I complained bitterly about the font and comments issues; I'm surprised he didn't tell me he changed the behavior.)

(edit: Tried it out, and it still isn't as usable as the website. It still has larger fonts and only shows three short lines from each comment at a time. The list of articles also has variable sized rows that often overflow onto multiple lines with other text at the same level: difficult to skim the titles quickly. I'd much prefer a subtle change to the mobile HN website to fix the buttons ;P.)

There are a few Android apps as well.