A while back I bought and reviewed the Vinturi, and concluded that it only improved 5-10% of wines. It is also something of a hassle to use, and so I've only used it with wines that I thought really needed the aeration. More recently I received this item as a gift. As an aerator it performs much like the Vinturi, and I'll repeat what I had to say about for the Vinturi at the end of this review. First, though, the differences.
Unlike the Vinturi, which you use between the bottle and glass, the Wine Finer goes into the bottle and serves as a pourer as well as an aerator. This is far more convenient than the Vinturi. You do need to be sure you have it seated firmly to avoid dripping. But when properly seated it pours about as well as the round disks you roll and slip into the bottle; it does have the advantage of having a plug to seal it, so you can stop a bottle without removing the Wine Finer. It also has a built in filter, which is more convenient than the filter you can insert into the Vinturi. So I find myself using this more than I ever used the Vinturi, even if I don't expect it to do much with the wine.
As for aeration ... I'll repeat what I wrote about the Vinturi:
Does it make the wine taste better? That depends on whether the wine is enhanced by the aeration. For wines with aging potential that aren't yet at their full potential, some air can help. Some "big" wines need air when they are "released" from the bottle. On the other hand, more delicate wines or wines on the downside of their peak can be hurt by aeration.
Most mid-level wines released today are designed to be ready to drink right out of the bottle when they hit the market. They are seldom much enhanced by aeration. And poorly made wines aren't going to be fixed by this device.
In my experience about 5-10% of wines actually benefit form this gizmo. And I won't use it with a really good wine--for those you should plan enough time in advance to let them breath in the bottle or decanter.
In summary, there are times when it helps, but it is not going to provide a daily improvement in the wines you drink, nor magically fix the clunkers.
The Wine Finer has the same limitations as the Vinturi when it comes to improving wines. But it is much more convenient to use, and serves other purposes. That makes it a more useful gadget, and one that is easier to recommend.