I have the X 8 that the dual syatem were the X4 is the sigle light imo the lights are well made have very good run time depending on were u set it and the spot light light unit that comes on the X4 works well but I never get much faster than 23 mph and only that fast in spurts and I can see fine with my 53 year old eyes I have run mine with just the spot on that would basicly make it a X4 and I see fine. As far as quality imo there built well work well and are worth the money but that's just my 2 cents I have had mine about 2 months $60.00 is a steal I know this was a old post I am replying to but I wanted to post after seeing somthing about there quality imo there very good quality
Iam sure someone a disagree but that's why they make so many diffrent lights
