Freemium all the way... but with a twist. First and foremost develop the product to the point where your workflow works and doesn't break in the middle. Then open the platform out to the public for a dollar, of course with the exception to try it out for 14days. When they sign up you are able to build an email list and if done right that's enough marketing. Make sure you optimize your product for the most useful keywords and request to contribute a guest blog or guest blogs in popular blogs or buy ad space on buysellads.com, create an animated ad and let that run.
Do the usual as well, create a twitter and facebook app. Release a Short ebook on your website on some important problem that your platform fixes, write a press release and reach out to your friends to share and re-share one of your blog posts on social media.
And by then you'll be quite famous and if your product is very useful you'll also be cashflow positive, resisting the temptation to say, "rich". Then you can do a update coupled with an email blast and you then release your finished version as an update, and monitor and learn from your users via intercom.io.
--> You are now Two years in the future and happy <--