I like your 2) - especially how Stealth Mode can be set up to mask browser-related stuff...What made me decide to go to Adguard after being a long time uBlock user:
1) Centralized database. No need for every browser I use to have a plugin download exactly the same copy of the database.
2) System wide ad blocking. Have you ever been pestered by the announcements in Skype, for instance? Tell them goodbye.
3) Android version. Seriously... use any android device with adblock on it and see how your data usage goes down. It's amazing how many programs try to download ads in the background while you're not even using them...
In regards to 1), I've never had an issue with database centralisation. As we already know, nearly every installed application requires an update or upgrade from time to time. It's just one of those things that can't be avoided. But from an adblocking perspective, it is great to have it all handled by AdGuard (apart from NoScript plugin, which I update noscript.untrusted in prefs.js), especially if a user makes use of Sandboxie for browsing (can create strong block rules), Shadow Defender (no need to exempt files/folders), and various other apps.
In regards to 3), I haven't tried the Android version yet because I only really visit 3 websites on my mobile phone. So I just went with AdAway. For the more browser-loving mobile user, AdGuard would be a nice choice.