It worries me when the first two sentences contradict each other: "Paymill enables you to offer credit card payments on your website within a short time. There is no waiting time" Which one is it?
I hope it's the real deal because the world needs it (we deal with a lot of non US developers around payments all the time so know the pain). But Stripe hasn't nailed it and Braintree couldn't nail the "immediate sign up" outside of the US so I too will wait to hear if it's all that much different.
Lastly looks like just Visa/MC. No AMEX or Discover which isn't the terrible but worth noting vs other options. (AMEX is more expensive so not having it I'm sure helped them get to 2.9%)