Pros: Price, Zoom Range, Optical Quality
Cons: slightly soft images at 500mm, need for faster film
This is not a Lens for the Faint-Hearted. It's relatively heavy compared to 70-300 Lenses that most people interested in this will have encountered, and a lot longer. You will need a Body with a good grip to hand-hold this lens, (I use both an EOS10 & D20) and even then it will take practice.
Having had this lens for 6 months, I'm happy to report that Picture Quality is very good in up to 300mm, and good to 500mm. For the price, you won't get better. Tripod shots are sharp, naturally couloured with no Colour abberation apparent. I tend to use 400-800ISO film to compensate for the relatively slow apertures this camera has. Your shots will be a little more grainy using a high speed film, but well worth it to get that much closer to your subject.
Unless you are rich, or don't mind even heavier lenses, this is for you.