I've flown EGPWS both offshore and onshore. Onshore its the bees knees, whether you are IFR solid wondering where you are going to autorotate to if the driveshaft lets go, or stooging up a valley in fog and rain looking for a low pass to the next valley. Worth their weight in gold, best thing I've seen in helicopters since celphones and TCAD.
Offshore its a little ho hum - the hope is that it will save the poor souls that seem to have missed everything else like Charron pointed out. Sometimes it makes up (in a really expensive way) for those aircraft that don't have any kind of a moving map display. To save that expense there is even the Garmin TAWS option that in some ways is superior to the Honeywell XXII system commonly found in new helicopters. The problem with the EGPWS offshore is the obstacle database that is nonexistent in many parts of the world, and there seems to be no set mechanism for confirming that it is up to date.
I disagree that the radar will identify all obstacles. Think heavy monsoon and a letdown in some crowded field, where you're coming down to 200' and trolling for a rig. An EGPWS that identifies obstacles works exactly the same as a Garmin map display that has the rigs entered as waypoints. Perhaps someone can comment on the obstacle database in the Garmins because I haven't seen one yet.
I'm waiting for 212man to post a picture of his S92 panel with the userwaypoints displayed on his map screen, and with an ARA approach routing on it as well. Is it "truly superb" compared to poor Geoffincornwall's boat GPS in his Dauphin, or does it hold a candle to the Garmin 530 equipped C+ models? Curious minds want to know, and the sceptics need a photo. After all, surely most conventional types I've looked at lately seem to have some pretty impressive map displays. We know the S92 has to be better than the AW139 - GIC had it pegged right that a business jet navigation suite is going to be a rough fit to a helicopter - so lets look at something really comparable.