The explosion of IPS panels is because LG figured out how to make them really cheaply. And those economic, low-quality variants are called e-IPS and I have absolutely no doubt that we're dealing with one here. (Despite the fact that specs on eBay say S-IPS.)

Also, $337 is not only cheap - it's dirt cheap.

$300 for 24'' IPS is cheap. Courtesy of e-IPS, of course. A Dell U2412M would be an example.

A decent 24'' IPS display, say a Dell U2410, will cost $500.

A high-quality 24'' IPS display, say a NEC PA241W, will cost $1000.

A high-quality 27'' IPS display, say a NEC PA271W, costs $1400.

Welcome to the real world.