Seeking 17-35/2.8 G lens advice

Anyone use this very best G on their 5D, 7D or Alpha here? Any known problem such as front/back focus etc..?

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Mark
KM 5D
28-70/ 2.8 G
70-200/2.8 G SSM
300/2.8 G HS
100/2.8 Macro
APO II 1.4X
APO II 2X
50/1.7
Sigma 10-20
HVL-F56AM

7D/VC-7D
SONY F828
SONY W1
Want to buy: 17-35/3.5 G
For sale: Tamron 28-300/ Tamron 2X TC for Maxxum
http://www.pbase.com/galleryonmymind