Glass break recommendation

[mfarver]

I am looking to add a few glass break detectors to my system, (currently only covered by contacts) since my cats manage to trigger even pet immune motions. Does anyone have suggestions on which brands of sensors to buy and which to avoid, or are they all about the same at this point? I don't think I want to go with bugs (most of my windows have more than one pane, and I think the bugs are pretty unsightly), and instead am looking at acoustic sensors. Or am I just going to have a whole new level of false alarms from glasses in the dishwasher and stuff knocked off shelves.

It seems acoustic sensors are kind of pricey at about $40-50 nearly everywhere, even ebay.

Thanks
Mark