Weaknesses: Can be tricky to fit to your seatpost.
Overall: I've used this baby on flash mode all winter on unlit roads in conjunction with a smart rear LED on constant. Cars pass with loads of room and if you look behind you you can see the reflection on road signs at least half a mile away. Battery life not great but picked up a load of batteries from Superdrug dead cheap. Good also in the daytime, cars give you loads of room. Try it.
Strengths: nimh battery is a bonus at this price. good beams. look good.
Weaknesses: burn time but can be upgraded to two batteries
Overall: after lots of research i decided on this system and managed to pick it up for less than 80ukp. good beam from the 10w and the 5w is fine for town use. as others have said it's not a smart charger so you can cook the battery if you're not careful. cars have flashed me due to the brightness and they always dip their lights. overall, good value and good performace.