There's an excellent post about the London Garden Bridge on the Being Brunel blog, titled "Why do we hate the Garden Bridge?". I don't think the author has covered all the bases, and he seems far too well disposed to the possibility that this unspoiled spot on the Thames could reasonably be home to a private garden. However, it's well worth reading.
I've discussed the scheme here before a few times - I think its failings are primarily political rather than in the detail of its design.
I'm interested in what others think: should the Garden Bridge be built? Will it get built? Please feel free to post in the comments.