Don't mean to hijack the thread off topic so I'll add I considered keeping a wireless pointer/slide advance device in my meeting bag but decided to just use a wireless mouse. Mouse works good with PowerPoint and saves carrying a second device.
That said, your comments on the PTV3000 and Screenbeam are appreciated. Any recommendation on a USB adaptor for transmitting for those computers that don't have Miracast built in or a wireless card? If so, do you have any experience with the range of the devise. I noticed Screenbeam has a kit that has the receiver and a transmitter.