If you want a good harness then Sabelt or Schroth are the industry standards. Many of the Sparco harnesses etc are actually Sabelt. Have a look at the adjusters, some are nightmares...generally the alloy being more expensive function better.
That said as long as you know what you want...3", alloy or steel adjusters....saloon style, 4/5/6 point and you are not worried about brand then OMP, Sparco, Willans, Racetech, Velow, Takata, RPM...just shop around and get the best buy.
Also, when looking at ebay and cheap harnesses...often the cheap ones are 2 or so years into their validity period.