I've been using my iLok 2 for about 7 or 8 years now.
Not one problem with the device.
There was short time (1-2 days) where iLok severs were funky, but I've never had a problem with the physical iLok.
I even pay the $30/year for zero downtime (insurance against theft. loss or damage to the device). I have a spare on hand at all times. Have not needed it yet.