This is were I get my screws, they are good quality and inexpensive. And the service is great.
Stainless screws are softer than alloy, I use alloys. Stainless is pretty and wont rust but the heads will strip much easier than alloy.
Only use good quality hex wrenchs and avoid using the ball type wrenches unless the screw is loose.
http://www.microfasteners.com/
joe