I don't know about that lens specifically, but most people are happier with the results when they save up for a bit longer and get a 70-200 instead.
The pictures captured with the 70-200 are orders of magnitude better (and you have at least one more stop of light at the long end). I have never heard of anyone regretting buying a 70-200. Buy used you will save money and can always sell it and get your money back.
What are you planning on shooting with this lens? If you are trying to shoot wildlife in good light, maybe 70-300 will work, but if you are expecting to be able to capture a kids soccer game in the evening, it won't be very useful.