I find the rubber Vacuvins work on a flat red quite well, if you don't keep pulling the stopper out on a tasting table. For an older, or delicate wine though, I find that they 'appear' to pull some of the life out of a wine, particularly pinot noir, if used over a longer period, but that will be the time open, and volume of space left in the bottle; so for me, the jury is out on this one for a fine wine. I find them best for young deep and dark rhone wines, or heavier new world shiraz mixes
For the Bosca malbec, I have drunk this at one 'glugging' sitting with my son-in-law on two occasions, he quaffs the style
and ends up drinking 2/3 rds I'm glad you said that Pontac, because the spice twist, vanilla and age of the vines did make this one a decent cut above the norm. Clearly though, on the tasting table over a period of a few days, I can imagine how this would deteriorate to a soupy dullness over time. . . . . I had a Mary le Bow 2005 2 weeks ago, with both son-in-laws' for Sunday lunch, large glasses, truely wonderful for 1 hour, then the beauty and complexity expires, quickly indeed. Do not Vacuvin this M le B '05, or . . . I regret, it would be dead and buried the next day.
The fridge and the cork for half consumed, young PN. Diam synthetic corks seem to work best for this.
I'm drinking a pleasant 2010 Bourgogne at the mo, half of it in the fridge for 24 hours, and it is warming up. My experence with these generally, that they may retain more of their beauty when immediately re-corked and held at 7 or 8 degrees C or so.