I've been using this razor for a few weeks. It does take its own multi-blade cartridge, but displays a big advantage -- more space between the blades than a Fusion. This allows the hair to be rinsed away easily without the razor clogging up into unusability. The cartridge flexes even between the individual blades.
I can shave less frequently and still get a close shave, because the blades aren't all gummed up. By the way, I was gonna post a review on Amazon, but apparently, they don't sell this. Their own site is defenderrazor.com. (I have no deal with them of any kind; I just like their product.)
The razor comes with your choice of handle styles -- regular or circular. (??) The blades come in regular, sensitive or extra sensitive. I tried both handle styles, but the circular features 2 cartridges and a learning curve that I decided to skip.
Nevertheless, I recommend this product for head shaving, especially with the sensitive blades.