I’m very pleased with mine. Not sure I’d want to leave wine in them for longer than ten days but so far results have been good. I only ever have one glass of wine a night and so always take at least 5-6 days to drink a bottle. In the past I have used canned gas, which works pretty well but is a bit of a pain and a bit hit and miss, and an “anti-ox” stopper, which is supposed to absorb the free oxygen in the bottle and which worked surprisingly well. In the past I have also used the vacuum pumps but have always found they leave the wine tasting flat. I have so far found the my etos work better than all of those techniques. So regardless of their actual performance I’m already on a winner compared to previously.
However I’d go further than that. When I’ve used the etos with cheaper young wines (that generally don’t last at all well once opened) I really haven’t noticed any change for good or ill over about a week. Two examples of such wines I’ve had recently would be Lascar Carmenere and Nero d’Avola La Ferla. Both were as lovely at the end as they were when opened.
When I’ve used them with more structured wines that could use opening up a little it seems to have worked well too. In this case I generally pour and leave it open for a couple of hours, as I would a decanter, and the wine opens up just fine. It does continue to develop after I have closed it but, since I have a glass every day and so am opening it up to the air every day, that’s only to be expected. But after a week such wines are still much better than with the other methods and I find they are usually just a bit softer. A recent example of such a wine would be Domaine de Thalabert.
And at the farther end of the scale I’ve also kept a 1999 Chateau Musar in one for about six days, opening it for a glass every night, and here I really noticed little change at all.