Its a bit of a minefield isn't it? Carparts4less are the same company as Euro Car Parts, AutoDoc and Onlinecarparts are the same company.
I wouldn't use LLLParts, read the online reviews, or look at the flashy website and then the contact us section at the bottom to find the address and google map street view it, it looks a little strange.
VBT discs are Awesome GTi the retailer, I wonder where they get the discs from?
Mtec are a company in NI but seem to be a cnc milling company? So likely get blanks and put grooves in them?
Go cheap save some money and they will likely be ok especially if you just bimble about in the car.
Go genuine or a UK manufacturer of brakes with at least some level of quality control like EBC (not that I have used them recently), but Freedman Automotive (EBC) have at least a level of control over the product, unlike ECP that are selling Pagid and Brembo from anywhere.