I installed sync yesterday, and it's nice. It's very usable without paying for it. In fact, the only reason I could see paying at all is to support the creator. The ads are negligible. I had to look for them to notice em. Basically if you don't wanna use it, don't. Not very complicated imo. There's other apps and the web browser. Your paying for the interface not the content.
I don't like that it doesn't have top comment navigation (or I can't find it) and when you click on a inbox message it takes you to that message isoalted in a thread, no context. Again, I might be missing something here...
I was literally just realizing that now. I just checked inbox for the first time, and it's pretty annoying. I would mind less if there was at least the entire comment chain within that top comment, cause I often forget what the hell I even said. I was using jerboa before, and there are features I'm really really missing. Sync would be great for perpetual lurker, but I'm addicted to commenting lol. No post creation also a drag, so I'll just use sync and jerboa in tandem for now.
This may be just my own individual experience, but the ads were worse before he released the first patch. Now I barely see any ads unless like you said I'm looking specifically for them. Although I'm used to RIF which had the same amount of frequency in ad space so I might be slightly biased.