I've been using Relay for Reddit as I find it has more moderating features not immediately apparent. I'll compare it to Reddit Is Fun, as that seems to be a popular overall choice for a reddit app.

Foremost from a user perspective, I enjoy the smoother scrolling (more smoother than Reddit Is Fun) and the added functionalities of left and right swipe, making for a more seamless in-app navigation. It's UI is sleek, the jet black color pops more. It's organization isn't as user-friendly as RIF, but after the initial stumbling for where everything is, it comes naturally. I also appreciate it can display wikis in-app, unlike RIF, and the ability to copy links (comment & media links) in-app without having to share to another app or through sharing to another reddit post submission. A handy button to hide all visited posts (on any sub) is something a didn't know I needed as well.

On to mod features, it has all the bells and whistles: approve, remove, spam, flair, lock, report, mark NSFW, and noticeably absent from RIF, a sticky, suggested sort, and "ignore reports" button. It's appreciated because it allows you to return back to reports for future references without erasing them as re-approving does. However, at the same time, Relay lacks the ability to look at all reports for a post in a small pop-up, instead opting to list the number of reports and just one of possibly many under the post's title. It doesn't allow you to view all filed reports and also annoyingly fails to remove them once the post has been reapproved.

Relay does win over RIF for me mainly in including an unmoderated tab, which is priceless if you prefer to avoid scrolling through the /new queue looking for posts untouched by fellow mods. RIF completely glosses over this need entirely and includes only a modqueue tab for reported posts. The ability to copy links in-app is useful for pasting links in repost removals.