EF 24-105mm f/4L IS USM vs EF 28-105 F/3.5-4.5 II USM

Well, I've never owned an L or an IS lens, so maybe this is an apples and oranges thing.

The reviews I've read for the 28-105 look pretty good, and it's $1,000 CDN less than the 24-105. Has anyone here used both? TIA.

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Mississauga, Ontario, Canada

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Canon Rebel XT / Nikon CoolPix 4500
EF-S 17-55/3.5 • EF 50/1.8 • EF 28/1.8 • Tamron 18-200/3.5 • Sigma 20/1.8