I feel nearly alone in preferring connect. It's still a bit glitchy but definitely very usable and above all: clean. I feel like the other apps all have a bunch of texts sizes and visuals I don't need. Connect just feels like a cleaned up reddit UI to me. If boost ever comes out I may switch to it, but I've already been feeling like connect is what the UI "should" look like. Others feel oddly busy to me
I find the connect UI to be really similar to Sync. They both group the vote buttons on posts, unlike all the alternatives, which reduces visual clutter and the icons and layout seem well designed in terms of icon and text size and margins looking symmetric (looks less like a backend dev just threw all the buttons vaguely where they're supposed to go).
One thing connect seems to do better is that collapsing a comment collapses the comment itself and not just the replies (makes it easier to move down a thread by collapsing each root comment). On the other hand, the tap target for re-expanding the comment seems to not extend the whole width of the collapsed comment.
I'm in a similar boat to wanting the reddit app but cleaner and not buggy. So connect and sync are my top 2 right now. I didn't mind the reddit app UI it was just so buggy and laggy.