This is focussed on Android clients as this is the only mobile platform I use.

• Most of the Android clients I tested are open-source projects, community-supported at best. For a lot of them, support boils down to either talking to a developer or app account on the Fediverse or filing an issue somewhere on github or a similar site.
• A lot of them are to be found in various F-Droid repositories.
• Most if not all of them are built by individual contributors, and maintenance / update frequency drastically differs. If one would consider projects alive only if they've seen changes or update releases within the last six months, most of these clients would fall through that filter.
• Though feature sets and approaches drastically differ, all of them seem to have equal amounts of advantages and drawbacks so it's rather hard to find /that one/ that stands out even with somewhat clear priorities in mind.
• Though I'm mostly using them with/against Friendica, pretty much all of them except maybe AndStatus specifically are Mastodon clients talking to the Mastodon client API so they're limited to servers that support / implement that API.

Arguably one of the oldest Mastodon client apps out there. Feature-stuffed, yet slow at times and modestly well maintained.

• (+) Rather good at dealing with remote content (like fetching profile infos, full threads, … in case data is missing locally which happens more than often).
• (+) Media previews in notifications.
• (+) Rudimentary filtering of notifications by type even on Friendica that doesn't support that server-sided.

• (-) Maintenance mode is unsteady. Sometimes, a few point releases pop up within days or weeks, sometimes it takes months or longer for any update. Same goes for responses to tickets. Mainly seems a project driven by one developer who has a different focus at the moment.
• (-) In some(?) situations, the app suffers from interesting performance aspects that make using it no real fun.