On the soft phone we have our 7 users setup to simultaneously receive calls. So all seven users see the incoming call if nobody is on the phone. Every user has complained about how annoying it is when they are in the middle of typing an email or inputting information into a form and the incoming call interrupts the typing. I think the softphone should pop up and notify but just be on the background and not override a user in the middle of typing.
You sometimes have to move the mouse back over to the box where you were typing to resume. Especially for our growing business that gets a ton of inbound calls, this can be quite bothersome.