Should I get the FHI Runway flat iron or an Onyx HerStyler?

I've been researching flat irons for like a week and I really need one! I've always had cheap ones that really damage my hair. I've heard good and bad things about CHI, and I don't want one of those... but I'm not sure if I should get an FHI Runway or Onyx HerStyler. An FHI is considerably more expensive, and I just wanna know which is better from personal experience.