Jim: I still have one sitting here but I have not gotten around to testing it. Check with Brandon at AO, I know he uses them. rfdesq does have a point, but it all depends on your usage and requirements. Is the motion for security or automation, or both? If used for automation then placement is alot more critical. I tend to agree with RD strictly from the standpoint that I am a firm believer in perimeter security as your primary focus. Stop someone/sound sirens BEFORE they are walking around in your house. In that vein, the Glass Break is more important than the motion, but I would also make sure I had properly placed contacts and/or vibration sensors, wired screens, etc. Glass Breaks are pretty casual as far as placement though, so I think in most situations unless you have strict placement goals for the motion base on automation needs, a combo should work pretty well. Keep in mind the ceiling based PIRs as in the BV have a different sense pattern than the wall mounted ones and are useless if you have pets. You can look at the spec sheets for the PIRs and they will show the coverage diagrams and patterns. Aesthetics also may play a part. The BV500GB is a rather large device that will sit prominently on your ceiling. Using the 5820s and small PIRs like Visonics you can get a very unobtrusive look. So there are a few more things for you to consider... But talk to Brandon, he will tell you like it is based on his experience, not salestalk.