It is marginally legitimate. To the best of my understanding (I've asked about it before, but I might have misunderstood the answer) They are a Teksavvy wholesaler, so they are supposed to be rebranding rather than using Teksavvy's name. You are not really a Teksavvy customer exactly when you order with them. In particular, payment goes to them, and they then pay Teksavvy for in bulk for all their customers.
By comparison, I'm a Teksavvy reseller, so I use Teksavvy's name all the time. When you sign up with me you are paying Teksavvy directly and you are a full customer. Teksavvy pays me a commission.
I believe the reason they can offer big discounts on unlimited is that they only buy 300GB service for those accounts from Teksavvy. As we know, there is no usage meter...
And then of course there is the no shipping, which is easy. They buy bulk modems from Teksavvy.
It is an okay deal, but mine is better (as in, completely straightforward about everything, knowledgeable about the service, willing to take the time, etc. etc.