Currently developing tools to do market research and user analytics on Instagram. Experience so far with the Instagram API is quite positive. Take a look at the endpoints on their dev page and its immediately evident: Instagram exposes a lot of precious data. Consequently, it is the platform of choice for users who accept sponsorship for posts. Also, when reaching out to the Instagram team about improving tag discovery and search, they were very amenable :)

If anyone from Snapchat is monitoring this convo, I would implore you guys to prioritize your API rollout. Provide the tools that allow your users to be able to make data driven decisions. Building an ecosystem of creators who can figure out how to monetize their Stories better than any one else can is "the key"