I used to use "MiniHack", but it seems to have gone out of maintenance and no longer works. This was the best one by far, that I found when I searched last time.
So far, I've tried HACK, Starling, and Hackers. I haven't been impressed by any of them. Octal looks like it might hit the spot, but I'm loathe to spend money on apps without much to go on...
* High-quality reading experience. Appends the title and other helpful info to the message if you want to share something, and provides easy options to share the HN discussion or the original article. The UI also prioritizes reading the discussion first which, let's be honest, many of on HN are known to do. ;)
* It mostly stays in sync with the front page of HN (and you can keep scrolling down, making it easier to read stuff that has fallen off the front page but is still valuable).
* The search function finds what I want about 80% of the time.
* You can log in with your HN account and see account stats, I sometimes see issues with the account stats (recent submissions, karma, etc.) staying up-to-date, but that's not a big deal to me.
Even before last weeks changes in HN’s HTML that broke MiniHack beyond use, there were quite a few bugs on modern iOS. Still MiniHack was the best.
Currently replying using HACK
The app is privacy-first; no tracking or analytics SDKs are installed. You can log in with your username, upvote, downvote, and comment. The idea is to provide as close to the web experience as possible in terms of "feel" and not to add any extra flair.
I'd love to work more on it, so if folks have any ideas with respect to monetization or marketing, I'm all ears! FWIW, I've been recently toying around with the idea of just open-sourcing it and making it donation-only. Haven't really come to any conclusions yet.
Also, I'm aware of some UX/UI issues with the latest update—it had been a while since the previous build and recent UIKit changes have created some wonkiness. :)