Nah, it's not that big a deal for me personally but it did piss me off. And on this kind of revenue it's important to get it right. From my point of view it would have been far better to hit me up on first load then resorting to interstitials on first feature use. I'm much more annoyed by the mechanics than I am about the ask. I get irate when the same basic mistakes are made over and over again by the same people. Even worse when they get in my way when i'm working.
Basic user: I dropped a file into a note and it's asking me to upgrade to premium. Essentially spamming me in product. Is there something wrong, if I wanted your premium teir i'd get it trust me, what I absolutely pay for is not to be hounded as if i were a free user. What in gods name are you guys thinking?