I have full fledged integration of google maps version 2 in my web application, with features like get directions, cluster markers, tabbed info window, context menu(right click). The implementation has very poor design which is causing some problem, So now I need to revamp the core implementation to better design. I was thinking of upgrading to version 3 of google maps API. Please suggest, if that's a good thing to do and my all features will be running fine(or I will get replacement for all the features mentioned) in less time. Or should I stick to the version 2 of the google maps API?
I recommend you upgrade to v3. I upgraded my site a few months ago (and blogged about the experience). A few things to keep in mind:
Once you are done, you will be happy to make the change. Pages load faster, zooming is smoother (polyines scale as you zoom instead of disappearing) and the mobile experience is much better.