As others mentioned allready a on-access scanner costs performance.
Therefore it would be great, if it would be possible (as soon as the scanner is implemented) to auto-(de)activate it, if you're connected to a network or not. Especially for Notebooks this would be great.

BtW: Great Work!

what about accessing files on a usb drives and cds-dvds?

yes, of course this is a Problem, but you could add the possibility, if you enter the cd, to ask if the hole cd should be scanned...
The Network On/Off Feature should of course only be activated if you know what you're doing.
But it is much better than switching on-acces scanning totally of for perfomance reasons.

BtW On his Blog Mick said, there would be an alpha driver for testing, and it could be found somewhere...
Where?

it's in private testing at the moment. we will release a public beta when it is more stable