One good thing about the VoIP industry is that a number of companies have helped make VoIP a household name - Vonage, 8x8, MagicJack, SunRocket and RingCentral to name a few. One result is an awareness of the concept. Awareness is marketing for the whole industry. (Kind of like Microsoft with Lync or talking cloud all day. It raises the ocean for all providers.)
So many of my ITSP clients reference RC (or stalk them). They do have a nice website and have put in the long, hard work for affiliate marketing. Not easy to replicate either thing.
One ITSP chose to directly compare themselves to RC. See it HERE.
Keep in mind that when companies mention RC or others, it is because of brand awareness. It is your job to educate the customer on the differences. They will compare you like apples to apples unless you explain that you are a grapefruit.