Unlike what some folks have suggested, I don't notice any speed or loading advantages over the other native apps. Some of the other offerings may be a little better but the biggest performance gains when it comes to loading will come from moving off the largest instances to a smaller one.

The main differentiating characteristics IMO are below.

Pros:

• The interface is essentially the one from the Reddit app. It's a mature design in terms of polish and is overall more minimalistic and clean UI. I find it consistent and intuitive to navigate.

• Decent amount of customization. While not exhaustive, the options presented are all well thought out. This includes moving things to side bar, bottom bar, and/or a floating action button.

Caveats:

• Ads by default, with a $20 one-time payment option to remove them. There's also an optional subscription (or a $100 lifetime subscription) for added features, which will include push notifications. Prices may be much higher for some other countries as adjustments for purchasing power haven't been made yet.

• As an early build, some basic functionality hasn't yet been implemented including submitting posts or editing post titles. If you're a moderator, mod functionality and reports haven't been implemented yet.

• Like other apps that were originally for Reddit, there are still some legacy references to subreddits. Sync also seems to still use orange for upvotes and blue for downvotes, which is the opposite from Lemmy.

• It's closed source. Without OAuth, the Lemmy devs have discouraged logging in with closed source apps (although I personally trust ljdawson).

• Some people don't trust Sync having ad tracking built-in. They're disabled if you purchase ad removal. Otherwise, there was only one incident in the past where the app began injecting Amazon referral codes into URLs but this was reversed.

Way better UI and UX, more and better features and customizability. It's closed source though. This may be a deal breaker for some.

For me though, if I have 2 apps of the same quality, I'll obviously choose the open source one, but if one is clearly better than the other, then I'll choose the better app, regardless if it's open source or not.