Many people will dismiss fixed length lens preferring zoom for versitility. But this lens is one that has impressed me since buying so don't dismiss it without a glance. The build quality exactly what you would expect from a Canon L series. The clarity is awesome - pin sharp shots are virtually guarenteed. Its fast, as the f2.8 would suggest. It's light, compared to my 70x300 I.S. and its versitility aided by carrying a 1.4 teleconverter (I find the 2x teleconverter tends to create soft images). For wildlife shots this lens comes out tops - if you have the space its good for portrait work as well.