VTX is Powercolor,aka TUL Corporation there is nothing bad with them...For sure they ain't popular as Asus,Saphire or Gigabyte but price is of their cars is often 20% cheaper which is good offer since warranty is exactly same or even longer what gives brands above
Asus,Gigabyte,VTX -3 years warranty
Saphire,MSI,etc -2 years warraty