I have one of the goose neck versions. Looks good, but tends to crack at the bend. The newer straight version looks like a much better design.
These will keep the beer carbonated for at least a week, likely much longer. I've never been able to test that.
![Roll Eyes ::)](http://www.homebrewersassociation.org/forum/Smileys/default/rolleyes.gif)
Plus it looks good on the shelf in my brew room.