You don't need rear side visibility anywhere near as much as front side visibility, eg cars approaching from a side street.
If you need to be seen from the actual side its usually going to be too late. The best time to be seen is on the approach.
ps. I posted a video yesterday comparing radbot1000's vs a zebralight h51r if you're curious.
I totally agree that if lights or reflectors don't com into plat before the last 20 feet (1 second or less at 13-14 mph), they only inform the motorist what it is that they are about to hit. Any hesitation in their stopping the launch, and it is too late.
Agreed that the most dangerous side approach is the cross street ahead. My headlights do well for that at night as I have some side output from them, in the day, I angle them at 45 degrees so they shine into the eyes of drivers. They do not glare in daylight. Even then, I had a guy almost hit me and say he did not see me (he crossed while looking at an approaching police cruiser and not where he was going). It would have helped if he had actually stopped for more than a few tenths of a second and actually checked both ways, but what he did works 99.99% of the time for him, right? So you only fend off the majority. The bozos are immune.
Rear side view at night helps your lights be identified as a cyclist and kick in for my bike about 100 feet away according to my video. So I think that has value even for the cross street situation. The front left hook (for countries riding on the right, switch that for elsewhere) is mostly a headlight defense thing though showing where the back of the bike is so they don't graze you is smart. The rear quarter side output is important if there are multiple lanes and you an be eclipsed as well as to avoid so beamy a light that traffic in the next lane overtaking you can't see you well.
So the Turbo and Radbot 1000 are a bit too beamy but it gives them power at a distance. A pair angled out a bit is a good fix for that.
Also, wider lights are more fool-proof when it comes to aiming. I have the Cygolite Hotshot, and small amounts of play in my home-rigged rack mount cause it to wander over time, which dramatically reduced its effectiveness. The Blackburn Mars 4.0 was a much wider light and didn't have problems in that regard. It also drained batteries at an unreasonable rate, even when off, to the point that I would take my batteries out every time I was leaving it for more than a day or two.
Also, twisty roads. If cars are going to be overtaking you on a curve, you need a wider light. This is why I'm planning on supplementing my Hotshot with a floody or even uncollimated dynamo light as soon as I get the parts.
Thanks for posting the link to the review. I was searching for a good tail light and went with the review recommendation of the editors and bought the Portland Design Works Danger Zone Tail Light. I actually wanted a rechargeable that had internal batteries and had USB charging but decided rechargeable AAA batteries was a good alternative.
Interesting going back over that review - I recently replaced two 0.5W blinkies with a Philips saferide. No it's not as bright, but I'm not convinced that matters. Happy to put up a review if anyone's interested, but my thoughts aren't far off swhs's.