It works. Complaint from VO people, they can't see over it.
Hard to read scripted material.

I was skeptical when I first saw it, but it definitely does work. Its not perfect and a nicely treated room is better...but by dampening the vocal sound before it can hit reflective surfaces it seriously makes a big difference. Me and some friends took one and recorded several tests with it, and we were pleasantly surprised.

Some of our clients are vocal groups that can't harmonize unless they're all singing together. We've had good results with the Auralex Xpanders. Similar concept, and it does reject a good bit of the sound from the other vocalists bleeding into each mic. We position the singers a fair distance apart, all facing inward so they can see each other and so we get the most out of the null in the cardioid patterns. The Xpanders we use on vocal mics are kind of bowtie shaped, so you can still see over them when they're oriented horizontally. There's no doubt the Se is certainly a lot classier looking.

http://www.auralex.com/sound_isolation_xpanders/sound_isolation_xpanders.asp

http://www.cascademicrophones.com/SE_Reflection_filter.html

Hi

Personally speaking. Although it works really well, I find the SE Reflexion Filter to be far too top heavy...well if using the long attachment screwed into the filter part anyway. For me it had a tendency to stoop forward, this being moreso on carpeted surfaces.

I now use mine with the filter part screwed directly onto the top of a mic stand with the mic (on another stand) coming into the filter's conclave from above the outside of it like this:

Like others are saying, nought beats a well treated room.

Me? I'm now about to try the Realtraps Portable Vocal Booth, just for variety's sake.

LiD