I think it all depends on how much you use it. I had the 70-200 f4L IS and loved it, but just wasn't using it enough to justify keeping it. As much as it pained me to sell it, I wanted a 135L more and it fit my shooting style better. I used my 70-200 maybe 5-6 times in the past 8 months and have hardly been able to put the 135 down, so I think I made the right choice. The more I use the 35/135 combo, the less I want to break out the 85, so that may be for sale soon. I think everyone's kit evolves around what you are shooting. I had a kit mostly aimed at motorsports (7D, 70-200, etc) now I have shifted toward a more portrait/travel oriented setup. No regrets.