Rails 3 paperclip vs carrierwave vs dragonfly vs attachment_fu [closed]

Question

I'm working on upgrading a Rails 2.3.11, Ruby 1.9.2 app to Rails 3.0.10, and attachment_fu no longer works.

I'm looking at changing to paperclip, carrierwave, or dragonfly for file uploads, or maybe a Rails 3 compatible, maintained version of attachment_fu.

Which of these options would be the best to use in terms of performance, how well maintained it is, how easy it is to upgrade from attachment_fu, and maybe is it going to be Rails 3.1 compatible? What are the major strengths and disadvantages of each one?

Any insight would be appreciated.