So ordered one of these T6 1200 lumens USB rechargeable units. £18 and free del from the rainforest place. Seems decent enough, tried it in the back garden tonight in pitch black and it seems decent enough. Appears to have a sort of dual lens set up whereone of the Cree's is a flood and the other one is a spot to the centre. Proof will be in the pudding next week on my commute though, especially on the 640m tunnel section of the Union canal, Falkirk.
What I like about this is similar to you mattyfez - no need for external battery packs or cables. Compact and on the bars with no extra bits. You can also use a long USB lead to plug it directly into a powerbank if desired.
This came with a free rear LED light which seems plenty bright enough but is a bit flimsy so I don't expect to use it, I'll stick with my Smart rear LED I think. The light also comes with a bar mount which allows it to be detached quickly from the mount itself, again handy for parking in the bike park stands at work.
After I've been out for a dry run on Sunday through that dark, damp Union canal tunnel, I'll post back with my thoughts.