I have tested the Vinturi and it does work immediatley, both on the nose and on the palate. However, I do not own one. I either decant for all the reasons Peter listed, or I pour into wine glasses and let them air, as David indicated, taking a sip once in awhile to witness the wine evolve (I usually do this while preparing dinner). To take the guess work out of the decision, I decant practically every red wine I open with one guideline: older wines may need less time to fully open up and, if left to long, may degrade before you know it.
Unlike Peter, I always place the wine bottle on the table next to the decanter no matter how unattractive it may look.
"There is no green on this planet without the blue." Sylvia Alice Earle:American oceanographer, aquanaut and author.
When it comes to making this planet healthy, the next ten years are more important than the last 10,000 years.