I think most DX reviews are written by actual customers.
However, I submitted negative reviews of two different sku flashlights once, and neither review was ever posted. In an earlier case, I submitted a positive review for a flashlight and it was posted within hours.
I suspect DX simply takes the reviews favorable to their business, and deletes the rest.
I ordered from them only twice. In the first order, all the items I ordered were received in 2-3 weeks and worked fine.
In the second order, they sent me a $50 flashlight that was defective. I complained through their system, sent the flashlight to the Miami return "drop box", and some time later received a replacement flashlight. The replacement was not the exact same flashlight, but a close replica, and it was defective too. I gave up at this point, which I believe is DX's goal - to sell you culled second-quality product, at discounted prices, and if you complain they then wear you down with months of delays and pointless, inane communication. I haven't bought anything from them since.
To their credit, the cheap 18650 and 16340 cells and chargers which I purchased are still going strong, some after a minimum of 200 recharge cycles. So, I think it's safe to buy these from DX, but I'd be leery of anything more complicated or expensive.
If you google it (to which the previous poster alluded), you'll find review sites which rank DX with amazingly high seller ratings, right up there with Newegg, whose prices and service are exemplary. This doesn't jibe well with the average user's purchase experience.