Just to get the conversation started, I'll give you a few of my opinions.
My favorite network is Twitter. For me it's a no-brainer. I can interact with people in short bursts, connecting without losing large chunks of time. Also, I tend to like short, pithy statements, and Twitter is the perfect medium for that.
I also like Google Plus because I like the way it's set up. It works like my mind, grouping people into circles like friends, family and work associates. I also like that I have a lot of control over who I get updates from.
What I don't like about Google+ is that a lot of my contacts aren't active there. But the worst thing is that I can't access it from Hootsuite yet. I know the folks at Hootsuite are working toward that, but Google+ is the hold-up because they don't want to overload their network. I respect that, but it's still frustrating to have to hope back and forth between Google+ and Hootsuite all day.
Facebook is still frustrating for me, less than it used to be, but still a fairly significant irritant. I don't like the way professional pages are set up to only have large updates from the owner of the page. If someone goes on a page and posts something it shows up in a smaller feed on the right of the screen. To me, it makes a page look like, ME, ME, ME. And I really hate that!
I also don't like how I can't get everyone's updates in my Facebook feed on my profile page. I have to designate each person I want to get every post from. That's just not practical for me with the number of friends I have.
Okay, enough about me. Hopefully I've given you some things to jump start the conversation. Now it's your turn to chime in. Feel free to comment about any network, and ask questions, too.
Don't forget to join the conversation!