*using it on a Nikon (D40) Summed most of it up in the pros and cons. I love it, and yeah, any beginners I'm sure would be fine except the note I put below (regarding VR) but I think most people should be fine.
Zoom; The 300mm get's right in your face every time! Highly recommend it if tossing up between a 200mm and a 300mm, Simplicity (I looked at many reviews before purchasing this lens and alot of people complained of difficulty in using it, but I found this to be extremely easy, other than the macro...
Can be a bit soft on the macro; Only noticeable if blown up, but yeah, can be a bit, The AF; I know it is often mentioned, but it really is quite laggy; I don't mind and often will do a whole shoot on MF, you just have to be prepared to at times.