I'm in a similar boat... my speakers got so much worse after the app update. The old version was still buggy, but wasn't THIS bad.

Anyway, I think there might be some third-party firmware (or at least frontends) for Sonos speakers? I haven't tried them out yet (too lazy), but if you're the tinkering type, might be worth looking into? And if you find a good one, please do report back :)