Quote Originally Posted by thekingb View Post
Yes, it's your money on the line. But if you have some trust in the good folks of a forum (such as this one), the collective advice of people can be an important data point for a decision. On a larger scale, this is part of amazon's secret - lots of user reviews that build trust.

Renting a lens before buying is obviously a great idea (and probably worth it for very expensive lenses). But for a $600 lens, as a percentage of the cost, it's quite expensive.For the same money, you can (and I have) buy the lens, use it for a month, and resell it on amazon as "used-like new" if you don't want it (especially with L lenses). I did this with the sigma 8-16mm, which I used for a trip and then resold for a "loss" that was less than the cost of renting for a week.
I have really appreciated this groups advice and asked a similar question early last year. I was on a T3I (have since moved to 60D). I was debating similar lenses and ended up making the leap and going with the 70-200 F/4L IS. But I think I would have been very happy with the non-IS as well. To expand on rent verse buy, look for someone who has a good return policy. B&H has a 30 day return policy, so buying and trying within that window is cheaper than renting. I would only have to pay for shipping back.

Eric