I had a similar charger that stopped working so was in the market for a replacement. The only difference between this one & the previous one I owned is the cord. This model has a plug that detached from the main circular base. It is the cord that plugs into the wall. I find that if I move this around much that cord comes disconnected from my circular base. Thankfully there is a small blue light that is illuminated when it has power to it.
I have charged three devices at a time on this with no difficulty. It did not slow down the speed of charging. I've been using this for a few weeks and have had no problems with any of the USB ports not working.
It is a good product, I just wish the cord was permanently attached to the base.