I read about nio in several gadget blogs, and finally I couldn't resist the urge to try it. I'm not the most tech competent person, but the installation was very simple and straight-forward on my Blackberry Curve.
I initially bought it with a theft mentality, but actually it's come in handy more on a day-to-day basis for me. It saves me time when I'm phone-hunting around the house, and also has reminded me to bring my phone with me when I'm running off to work without it.
While I've not actually left my phone anywhere out and about yet, I do enjoy the peace of mind that having nio on my keys gives me. I tend to travel a lot so instead of being paranoid when I'm in crowded public transport, I can trust that the alarm will go off if anyone gets my phone away from me.
Only issue is that my schedule isn't very predictable, so I've not taken advantage of the calendar feature a whole lot. I tend to leave nio on for large chunks of the day, but I don't mind having to charge it up more often than if I only used it for certain periods. Overall I think it's a tremendous help to have a nio as someone who relies on my phone a fair amount (well who doesn't these days?), and I can see this being extremely useful for company Blackberrys especially.