Hi nilo,
No canister filter delivers it's rated flow. As they are filled with media and placed further below the waterline the work that the pump must do to overcome the friction presented by the media, and to overcome the weight of the water as it's being pushed uphill takes it's toll. SuperColey1 is correct in that the 10x filter rating recommendation takes all this into account. Filter vendors have not rated their filters for our use, just for the general population of fishkeepers so you have to completely ignore the data on the box. You can use one or more filters to cumulatively arrive at the 10X rating. Also you can use powerheads to achieve the total flow in circulation if economics prohibits you from getting the recommended filter size.
Buying a filter is a bit like buying a car. They all get water from point A to point B. Some are quieter, some are larger and some are less expensive to operate. In that regard a poll wouldn't really help because each person has a different idea of what the perfect car or perfect filter should be. Also, unless each person has tried every filter in a given rating there is no way to say one is better than another. Each can only subjectively say whether or not a given filter accomplished it's expected goal.
As long as a particular filter does not have a reputation of being overwhelmingly inferior or unreliable then it's better to simply get a popular brand in one's price range, unless one has a particular fetish for the features of a given brand. Eheims are noted for their quietness and workmanship for example, so many choose these models if quietness tops their priority list. Some have pumping power rated higher on their priority list and some of the Fluval models do better in that category.
Hope this helps clarify.
Cheers,