f4-5.6 L IS

The Canon 70-300 f4-5.6 L IS was announced in September 2010 and made it to stores at the beginning of November.  There already exists two 70-300s in the Canon lineup but neither of them have ever been showered with praise.  The previous 70-300 f4.5-5.6 DO IS lens was incredibly small due to its difractive optics design, but image quality suffered and it never sold in large numbers.  The 70-300 f4-5.6 IS (non-L) is a more budget oriented lens (approx. $550) and again never really turned any heads.  I heard a lot of people cry “Oh my god a variable aperture