I have the White Zone 5 and two Red Zone 4s.

The first Red Zone 4 I purchased in December 2012. The light worked fine for a whole year until December 2013, when the LED on one end refused to light up. I contacted Niteflux. Their responses were prompt. The light could be repaired by use of a soldering iron. Unfortunately I did not have one and said so. They then shipped me a replacement. So now I have two lights - one partially crippled. I use both for my weekday commutes to work.

I bought the White Zone 5 in September 2013. 8 months so far and no problems.

I have found that Niteflux is responsive to customer queries. If there are shortages in stock my feeling would be that they would tell you straight up and not keep you waiting.

I live in tropical Singapore, in the humidity and wet. The lights have fared well.

As mentioned by Athens80, the side visibility can't be beat. I understand that the most common form of accident is being hit from the side. These lights are effective.

I think the Whitezone 5 has a bigger battery than the Redzone 4, and though it has a higher output, seem to last a lot longer.

I like these lights. Also the Redzone 8 may be overkill.