Bryan already reviewed the new Tamron 150-600mm f/5-6.3 Di VC USD Lens. He says "This highly anticipated lens has been a very fun lens to evaluate. While autofocus performance and over-500mm image quality get my vote for this lens' weaknesses, the Tamron 150-600 still has a great deal going for it. The Tamron 150-600mm f/5-6.3 Di VC USD Lens is defined by attractive image quality over a great focal length range with a relatively compact, light, reasonably well-built design that includes Vibration Control and a very attractive price"
here is the link: http://www.the-digital-picture.com/Reviews/Tamron-150-600mm-f-5-6.3-Di-VC-USD-Lens.aspx