Prof2MDA,
I wanted to stress that in my opinion winglets are of most use at low speed, not in high-speed, as some earlier postings indicated. Somebody also stated that Airbus uses them merely for proper looks; if that's the case, I wonder why Boeing's 737's are now available with aviation partner's winglets, they sure are of some use...
Jambo Buana,
by the 4% penalty I was not referring to the climb GRADIENT, but to a calculatory adjustment of the approach climb limiting WEIGHT, which is with G/A thrust, landing flaps and gear still down.
When You mention Salzburg Airport I hope You already had a chance to enjoy the view onto Salzburg Castle...