Click here for a high rez pic.
The 300mm F2.8 lens is just not a good lens for birding. If AF were good then it would be border line. The 500 is the smallest I can really recommend for any birding. If it is strictly for birding. If you want a lightweight rig for occasional birding and for other things then ok. But strictly for birding it is a wash IMO.Click here for a high rez shot.
Will I continue to use it, yes. Will it go back to Canon, yes. I expect it will not be fixed.