Most of the folks here have pointed out that our HUD's in the Sluf and Viper and Jaguar and Tornado and Tomcat and Eagle and Hornet and Typhoon and Harrier and, and and, and........... were there primarily for increased combat effectiveness. No argument there. But as Turbine's article rightly points out, the doggone thing became a lifesaver when landing in poor weather and weapon delivery was not a factor. It definitely reduced workload for we folks that didn't have to deal with "CRM". Simply said, "Self, get your act together, and follow the approach plate and ILS steering cues".
@ OK The canopy distortion was negligible over all 360 degrees of view we had, and was optically reduced to near zero ( like a fraction of a milliradian) within the HUD FOV. See my landing in snow showers with the LEF folded up. That's the smaller HUD in the Block 10 or 15 Viper.
http://www.sluf.org/misc_pages/lef-landing.m4v
http://www.sluf.org/misc_pages/rightwing.jpg
You may call me a Hud cripple, as I used the thing 95% of the time when IMC, and cross-checked the steam gauges to ensure we were all a happy family. I have been far-sighted since a teen, and if I stared at the steam gauges for longer than 2 minutes, everything was blurry when I looked up - not good when breaking out at 200 feet and 190 knots as I did in the VooDoo. Learned not to focus real hard and survived easily.
For well over a decade USAF refused to call the HUD a primary flight instrument. As it seems some here are, 40 years of tradition unhampered by progress. Sheesh, if I have a relatively cheap display ( now that GPS, INS, FMS, etc are highly integrated via data bus and computers). what's the big deal?
As far as the Brits leading the way, they fly in poor weather most of the time, and their instrument skills are the best I ever saw. A HUD was a natural for them when landing in poor weather, regardless of the enhanced tgt acquisition and delivery capabilities. So my HUD time in both jets was courtesy of Marconi.
I continue to feel that a flight path vector display or symbol for the AF447 dudes would have helped a lot.