I still don't have too many people on Google+ but I thought I'd record my thoughts
I love them. Some people are a bit confused about them and consider it a privacy risk that people can add you without your permission. FB has the same problem but doesn't do a good job of telling you. In FB if you send a friend request and it is never accepted/rejected then your feed will display any public updates from that person. Google makes this explicit and emphasizes the benefit of it by having a "following" circle by default. I think it is a much better and simpler model than "friending" products and people or "liking" their Page.
I'm still playing with what I want in circles. Too granular of circles means you have a lot more to manage for each post. Right now I am looking at "family", "friends", "acquaintances", "local", and "professional"
For cleaning up my circles over time, I'd appreciate a mass-edit mode where everyone is a row in a table and the columns are the circles they are in. Bonus points for Google also showing who has not added me back and who I've not added back.
I like that when commenting on posts you can see what the visibility is of that thread.
Sometimes privacy on my posts isn't a big deal, like talking about programming for MeeGo. It'd be nice if you could use your circles not just to restrict communication but say "these people will actually care but allow it to be discoverable for people I'm not connected to yet".
Another variant of that global-sharing-with-focused-audience use case is my use case for Twitter. I originally joined twitter so I could track MeeGo Conference hashtag and know what else was going on around me while in attendance. A Similar use case that a friend pointed out is tracking live news for things like the Texas legislative session. I don't think I've seen a G+ equivalent system to hash tags but it will be hard for it to compete with Twitter without it.
This is one of the killer features, being able to check on my notifications within GMail.
It is nice that it is so easy to find how to provide feedback to Google on Google+. It is also a really slick tool. I've already sent them several items for improvement. I hope they roll this out to their other services.
Integration with other Google products
Currently there is some integration with Buzz and Picasa Web though I am unsure of what Buzz's role is now and am thinking of disabling it.
I am looking forward to this being improved. Good Google Calendar integration is a must for being a FB replacement. Blogger shouldn't be too hard to also tie in. I'd like them to solve the GMail / Google Reader integration issue but not too sure how they'll pull that off.
Contacts integration is actually where users will probably see the greatest troubles. This is due to trying to bolt together different services that don't always have their data coordinated. Users have unmerged GMail contacts, contacts creating G+ accounts with different email addresses than what are in my contact book, and the various tags I have from people. It'll be a mess even with Google's help to try to match up all of these representations of people.
Back to Picasa Web. I figured I should go back and update my tagging of people in my pictures. Sadly I can't find the really helpful mass-tag tool that lets you look through all the faces it found and tag them.
One of the reasons I am loyal to Google products (besides reducing the number of accounts I need) is the ability to leave and this is no different.
As I said, Google will need to improve their service integration and slowly ramp up their algorithms taking care of things for me.
Reaching critical mass will be a challenge. Some might compare this with the migration from MySpace but this is even harder seeing as there are even more users with more history in the service to leave behind. Maybe that is a good thing, to have a fresh start, but there are some connections that might not transition over that I would miss.
A question for me: where do I post things? Facebook, Twitter, or G+?