July issue of Sound on Sound Magazine has a review on this mic. written by Paul White, the chief editor of SOS Mag. Although you need to be subscribed for acces to the link, here is a copy/paste of the last two paragraphs of the article:
"I was intrigued by the Snowball's omni mode. Typically, omnidirectional mics have an acoustically transparent mesh covering the capsule, but this mic is totally enclosed at the sides and open only at the front and rear. I felt this must compromise the omni mode's performance to some extent. When I checked the polar patterns on the Blue web site, my suspicions were confirmed — the omnidirectional pattern behaves more like a wide cardioid at most frequencies and the sound picked up at the rear is much duller than the sound picked up at the front. The different tonality of the omni mode was also to be expected, as its presence peak is much higher than that of the cardioid modes. When te mic is used on-axis, the omni setting produces a nice airy sound which makes the cardioid modes sound slightly dull by comparison — almost like listening to a typical dynamic mic next to a capacitor mic."
"Cool Or What?"
"There's no denying that a buss-powered USB mic is a very neat solution to recording audio into a laptop or domestic computer system, and this one produces subjectively high-quality results, providing you use it close enough to the source to get a healthy recording level, by which I mean a signal peaking at -15dB or higher. In my view, the omni mode is best thought of as offering a different tonal flavour to the cardioid modes. Its pickup pattern is not truly omnidirectional and I wouldn't consider the mic to be well suited to recording round-table discussions in this mode, but used appropriately its sound quality is fine and the background noise acceptably low. If you are going to use this mic for Podcasting, it will produce the best results if you speak into it from around six inches away, and you can choose omni or cardioid mode depending on which tonality suits your voice best. For loud instruments, the pad is a sensible and welcome addition, but because there is no variable gain control you'll sometimes have to use the mic's distance from the source as a gain control instead, which may mean compromising on placement. I'm sure that we'll see 24-bit USB mics in the future, and hopefully ones with more control over gain prior to the converters, but at the present stage of USB buss-powered technology, where the amount of current you can draw is the limiting factor, the performance of this microphone is probably nearing the limits of what is possible"