Spring is finally upon us here in Northern Manitoba. I took my two daughters and went for some walleyes last night. The new 999 unit performed tremendously. It tracks bottom at full speed (35 mph) perfectly. The side image and down images were very clear when I was moving at close to the scroll speed (3 or 4). I'm sure it will take a bit of time to get really good at getting the clearest pictures possible. So far VERY impressed, coming from an Eagle FishElite 640c.
Only one minor issue - the tracks on the chart window seem to be off-scale from the map (zero-lines map from AutoChart) at distances from the boat icon on the screen. I noticed this when traveling back from the fishing spot and my track was going over an island, but as I got closer the track drifted over to the proper position (the channel between the two islands). Maybe this will be fixed with a software update...?... but it's not really a biggie right now.
Overall, the sonar is very impressive. I'm seeing fish, structure, depth transitions - all the things I bought the unit for.