I'm not really used to giving ETA's to the FIS controller.
If he's radar, he knows where I am and when I'll get there better than I do.
If he's information only he couldn't care less ! He just needs a rough idea of where I am going and let me know of any traffic.
Happened to me quite a few times that I am receiving FIS from a radar unit just outside their zone and someone else is flying in the same area but they're talking to a FISO. Saw them zooming past 500ft below me, they probably were on a FIS "No known traffic to affect you"
Obviously nobody's fault, in class G.