As with many recent Google products, I like the idea but I think the implementation is poor.
For one thing, responses on Buzz are automatically sent to your GMail inbox, and there's no apparent way to change that. Thankfully, Lifehacker has
posted a solution, but the Google developers should have known people wouldn't want that. This isn't the first example of Google lacking foresight with their changes: there was a minor uproar last summer when they modified the labeling system in GMail and disabled right-side labels. It took months before they implemented a "hide read labels" feature so users could recover the lost screen space by forcing labels back on the left side with everything else.
What's worse with Buzz is that they're automatically connecting you to a "starter" group of followers, supposedly based on how frequently you contact people. This has led to people being automatically connected to landlords, former stalkers, and other people they do not desire to share things with (actual examples from Google's help forum which I have been reading). What really makes this upsetting to me is that Google had the EXACT SAME ISSUE about 3 years ago when they made shared items in Google Reader more public. People were upset about it then, and they're understandably upset about it now.
It's more upsetting to me to see that Google has not learned from any of its past mistakes than it is to see the implementation of Buzz is not perfect.