Got both…
Used to have a joystick on the helmet and an older Gloworm on the bars, worked pretty well but the joystick beam pattern is very “spot” if that makes sense.
Then splurged on a six-pack from Evans in their 30% off sale and found the joystick got completely lost in the light from the six-pack.
(I hasten to add I also tried a Maxx-D and thought it was great, but couldn’t justify NOT spending another a few pounds on a six-pack!)
Then bought a Diablo (just caught the end of the same sale) and found that although its beam was still almost lost in the six-pack when looking forward its spread of light was much better when looking around on the trail, technical corners etc, when the joystick would just illuminate a small area. it defiantly doesn’t throw was far up the trail, but your depth perception and general see-ability are much better.
The Diablos battery life is a bit pants though, I had to buy a support cell to run it on med/high power for anything more than a 1hr ride. The TAP function is bloody useful though, even if you do look like a bit of a pillock banging yourself on the head at the start of every decent!
I do now think I have a pretty perfect set up, and the joystick has been moved onto the bars of the road bike to use its endless battery life on flashing mode.
HTH, Dicky