I have one. The vacuum function is good enough that the cork is tough to pull out 2 days later. I wouldn’t try to defend a claim that it is otherwise any better than just replacing the cork.
If you need to make wine last a while (for example you live alone and like a glass of wine with dinner but not a whole bottle), best is to buy boxed wine. Unfortunately, it is harder to get decent wine in box form in the US than it should be. (There were some very drinkable Malbecs available in boxes at the local Norwegian Vinmonopolet when I was living there.)
