Super lens for amateur photographers like me - buy recommendation

For some time I was no longer satisfied with the kit lens of my Canon EOS 450D and came across when searching for a new on this Sigma. For the price of about EUR 400, - I can not find anything comparable. Had the opportunity to test before buying the lens from a friend, it was a clear decision to buy. Here are a few facts

+ Super light Stark (2.8)
+ By the large Belendenöffnung Unschärfeeffket in depth even at low zoom
+ Autofocus accurately and super quiet
+ Manual zoom is schwergänig enough to set it exactly
+ Works well with external flash (Speedlite 430) together
+ Sun visor is included
+ I am completely satisfied with the results in both indoor and outdoor shots and in poor light conditions (church).