Sell Canon 17-40 for Tamron 24-70 f2.8 VC

Has anyone sold their 17-40 f4 L for the new Tamron 24-70 f2.8Di VC. I have owned the 17-40 for 5 years now and it doesn't come out of my camera bag now that I shoot mainly my kids on a 5Dc and 1D MKIII. I used to shoot landscapes and wish to go back to that whenever they grow older and I get any spare time back. I own a nifty fifty, 85mm 1.8 and 70-200 2.8 L but don't have anything at the wide end for use indoors in low light and high ISO. Alternatively I could blow the budget on the new Sigma 35mm 1.4......

I guess I am really wondering if the Tamron is versatile enough to be used for both low light family/kids and landscapes as I don't want to lose the 17-40 to buy one again 5 years down the line.