Had the Nightbreaker H4 on my previous bike (Kawasaki ER5) and although it didn't do much to improve road illumination (I blame the Kawasaki's headlight for that) it did wonders on improving my visibility because the headlight burned much brighter.
Even if the only thing they do is make me more visible I think they're worth the money.
As you likely saw in the forms, I've put LEDs in, replaced both the H4 and H7. One was dead-simple (on my '05 FZ6), the other took some finagling (the wire-basket that holds the bulb was very snug/tricky) - sorry can't quite recall which is which (but I think the low-high/right-side was the easy one). No significant alterations required other than cutting/trimming the rubber boot, to account for the bulb shroud/fan (both size as it is wider, and to shorten it so the fan is exposed to the outside air). I'm reasonably certain I've improved the amount of light output (brightness), I feel like I have better throw/coverage on the roads, and I like that it decreased my electrical draw. Aiming it has been trickier, but that could also be me - I started out a bit high, and botched the instructions for adjusting. Can't speak to legality, either here (US) or in UK. Haven't gotten pulled over yet. I have a before/after picture on the forum (when I documented/did this), should be easy to find. It's not a great comparison pic(s), but maybe helps.