(I work at Stripe, here in London)
Great write-up - I hadn't seen that graphic before but it's great - full credit to the original source http://startingandsustaining.com/.
As a Stripe-r, I can't complain about the OP's conclusion in any way :) As stated they are based in Denmark, and Stripe is not currently available for Danish businesses - that's on us to fix, and we're certainly working on it.
However, re: the title "How to choose a payment provider for your Europe-based SaaS startup" - the situation in Denmark is not representative of Europe as a whole.
Stripe has now launched here in the UK[1], and we now have betas available in Ireland, France, the Netherlands and Belgium - with the latest released in the past few weeks. So if you're based on one of those countries, please do give us a look. And if you're based elsewhere, well - I guess we need to keep up the pace and hurry to your country ;)
[1] https://stripe.com/blog/introducing-stripe-uk
As other commenters have mentioned, it's really easy to make mistakes comparing complex pricing across different providers. With Stripe and PAYMILL, the fees quoted are all you pay. With Braintree's interchange+ pricing, they actually state themselves that "Total costs are typically 1.8% to 2.6% of the transaction. There is a minimum cost of €100 per month"[2]
[2] https://www.braintreepayments.com/faq#pricing-question