Many complaints only some of which come to mind immediately. Presence/status -- can't set it. Will I annoy this other person if I send a message? In busy hangouts requires that I scrollback to new messages, having to remember the last message I read. Can't search. One pile of people, big mistake -- no opt-out of this. Can't segregate people into different attention classes. (Just because I have 1000 people in a g+ circle doesn't mean i want them all to be able to freely message me, or even see my status). These are all UX issues. [Android client. Never looked at the iOS client]