I'm a sucker for plugins that specialize in one sound or just a few sounds, so of course I had to check out Bottle Pop. I don't think the blowing noise really sounds much like blowing into a bottle, but it is actually a really cool and usable sound. I think it actually sounds quite lovely, especially when you turn the reverb up, or use your DAW's reverb. The other sounds I guess are supposed to be the tapping on a bottle. These are useful as well.
I give it a solid 4 for the quirky GUI and for the nice blowing sound.
Nice idea, but based on the demo doesn't sound at all like the sounds from blowing on the top of en empty glass bottle. I say "based on the demo" because their site is all screwed up it didn't even give me a download option after I went to cart.