If a rider has only one lamp, a steady lamp is easier for other road users to position. It gets done by driver autopilot, normally. This applies to front and rear. Other road users are, after all, used to looking for other lit vehicles, which have steady big bright white lights front and red lights rear.
A blinky alone takes me a few blinks to target. A lot of the time I think I'm resolving their position by non-lamp cues (the luminous frock, often: retro-reflective really is very perspicuous).
I get a pair of uncomfortable impressions from just-blinky riders. If they're just rocking the death-blink up front, they're the confrontational, quote-the-highway-code-at-you type. A small part of me wants to bop them on the nose for being tossers. If they're just rocking a blinky red, or two, or seven, in a bandolier, they're the apologetic please-mister-driver-don't-kill-me type, and they almost annoy me more with such a conspicuous display of weakness.
Man, am I cranky tonight.
Fibreflares are pretty good, actually, though I don't think they're significantly better than a strip of red retro tape -- definitely not £30 better. I love retro, it never runs flat and it weighs nothing.
Full-on mental deep-sea creature lighting is a whole other game. That's the Pinkie Pie of the road, and like fibreflares, it's all just accessorizing. So long as it doesn't confuse your location or dazzle the operator of the death machine you want to avoid, knock yourselves out.