I'm also on Sync, but there are a few things I'm unhappy with that have me looking at other apps.

First, the dev isn't active on Lemmy. He'll make an announcement post every few months and reply to comments for a couple of days before going radio silent again. I'm worried he'll abandon the app out of disinterest or low motivation, like he did for a year after his UI refresh wasn't well received back in the Reddit days.

Second, that inactivity extends to app development. Major, easily replicated bugs (like the crash on startup if you have "hide account names" enabled) linger for weeks to months without a patch. This also goes back to the Reddit days and isn't new behavior.

Finally, he puts basic app features behind a paywall with a much higher price than normal IAPs ($16/year or $99 to permanently enable them). This includes features that used to be free in Sync, like tagging users or color highlights. It also includes things that Lemmy already does for free, like backing up subscriptions (though that was only recently added to Lemmy, so he might move it to the basic app eventually). Just removing ads with no other benefits costs $20, which is more than any app I've ever used charges.