Thanks for that i'm looking into this lens now it looks very promising, its nearly half the price of the 70-300 IS and seems to offer almost the same IQ!.. I don't think missing 50mm would matter too much.
To be honest I was torn between this lens and the 70-200, but as I had a bit of a windfall I went for the big white one, the only drawback for the EF-S is of course if you move up to full frame, this little fellow can't go with you.