Lenses for EOS 30D (1 Viewer)

I am Nikon user so am not familiar with Canon but I received the following message from a friend.

"My mate has a Canon EOS 30D but is getting disappointing results with his
EFS1855 lens. He is considering getting an EF quality lens - 18 to 200? Any thoughts."

If anyone can offer some help I would be grateful.

Many thanks in advance.

Daveash

The Sigma 18-200 OS lens is probably worth a look - I tested one a while back and was quite impressed - it's a nice zoom range, good image quality and the OS seemed to work well. All in it looked like a very good walk about lens.