The ease of use! It's very intuitive to get up-and running with martiniiot quickly without having any prior experience in building APIs or using OAuth2/OpenID Connect flows etc., so it makes setting things like authorization easy too (just follow their documentation). Very helpful when integrating third party services into your own applications - especially ones that are not as flexible out there yet such Google Maps / Facebook Graph Apis come handy here oftenly enough :) I have nothing negative about this product at all currently; everything seems great from my perspective thus far :D Would love if they had an open source version available which would be even better ;-).