I am finding this very true. I own three of the DX P7 light and so far they all have switch problem. I took apart two of the flashlight switch, clean them and try to get as good of a contact possible and it only lasted a week before they start to flicker again. The price is not to bad but the quality is horrible enough for me to rename Deal Extreme to "Dud Extreme".

I replace those P7 with a Shining beam MG P-Rocket SST-50. I placed an order on Friday and got it on Monday. It is a very good light. The light is much more brighter than the P7 and the MS light. I haven't got any switch problem like I did with the P7 either. The 18650 battery last me 60 minutes on high. The drawback is the price of the light at roughly about $70 after shipping and the fact that I had to buy AW18650 ($20) because the current draw from this light is over 2A which the Trustfire battery was noted to not being able to deliver the full current needed for this flashlight for max lumen, but otherwise it stil will work, just not as bright. The good news is that my charger from DX still works with the AW18650 and I saved a little of $ from that. I probably can use this light on Med and get away with it alone but since I got the MS900, I use that on strobe along with the P-Rocket is more than enough for any road I ride.

I'm not sure if you are incline to use AA/AAA battery instead of 18650, but if you do choose that route, I strongly recommend Shiningbeam for their flashlight that use those batteries.

Edit: BTW, this P-Rocket has a flood that cover the side of the road and the spot is good enough to see when riding at 15 mph. If I get to it, I may post a sample or two of the light output compare to a P7 and MS900.