I have not but I can tell you I get nervous when I see products that sell for less than 1/2 of what most every other brand sells for. Considering it is Brakes we are talking about you are wise to try and find someone with experience. I would consider them if it were a low speed less performance bike but I am not sure how much I trust low dollar imports.
I had a couple customers buy 525 chains off of ebay/amazon for close to $50 for a o-ring chain. That's less than 1/2 price of most chains that size. Neither chain survived a session on the Dyno (about 20 runs) from brand new they were stretching to the point of being worn out. Customers buy the cheap levers and find the hydraulics no longer work because the pivots are in the wrong spot or outright failures of the components.
I am all for saving a buck but when it comes to safety items (tires,brake pads,rotors,lines,masters and levers) I do not think it is a good idea to cut corners too much. There should be plenty of well known parts at less than boutique prices that get you a level of confidence. Not just "guess how cheap we can sell these for".
I guess the other thing would just be on stuff like brake pads, it's kind of good to know the characteristics of the pad to choose the best one. That said I bought some off brand pads once but I decided not to use them. I cheap out on levers and lots of stuff, but not tires and brakes. I look for a good deal but stick with name brands.