Yes .... absolutely!
I've had mine since Aug 2007. After initial set up and making sure router and adapters were updated (firmware), everything worked and has continued to do so. My husband swears at his computer much less often and now places all blame for his woes on Microsoft instead of the router/internet connection (he has bad karma with electronics). We have 2 desktops, a laptop, Pocket PC and hotspot phone using the router.
I also set up a DIR-655 at my sister's house: they have 4 desktops, laptop, 2 PSPs, Wii, Xbox360, and hotspot phone accessing their router. They have no problems with it and I haven't even gotten around to updating the firmware since the router was installed last August.
Both are set up with MAC filtering, broadcast SSID is off, and WPA2.
Hope that helps!