The phrase "big differentiator" means something that sets one thing apart from others by being unique, distinctive, or better in a significant way. Full definition
The customer experience is becoming the single biggest differentiator in today's competitive business landscape. (lexicata.com)
Nextbit's other big differentiator comes through design, with former HTC design lead Scott Croyle bringing his talents to the project. (androidcentral.com)
Apple actually has a real big differentiator here. (imore.com)