Hi all !
I have just bought a 17-55mm IS lens and I don't think it has a bad or low construction quality. I know that I don't have it for a long time, and that if I compare it to a L series lens it'll feel cheaper, but let's be honest: It's a damn good lens !
The only thing about it so far is that I just can't make photos at 17mm, and use the internal flash of my 30D...a shadow comes along with the subject of my photo; that's because of the 17-55 lens size, (77mm diameter) of course. Anyway, I don't like photos with flash, and that is one of the reasons I bought a 2.8 lens + a Image Stabilizer: to avoid using the flash to the maximum.
But as far as I can tell now, it delivers good sharp luminous photos !
So, BUY IT !
If I happen to have complaints I'll be back here to report... (Hope not though...)*
Check out this "baby's" size:
Best regards*