Hello Friend,
Doesnt look like a legit site to my.
Why?
- No KvK number (Thats what you need when you start a company in the netherlands).
- You need to be registered at that home address or else its illegal.
- Also cant find any reviews on dutch site(s) and its build at 2011.
Correction:
there is a KvK number for dutchmailer.com (first page below)
but the address on KvK is different than on the site, and a "suite"

?
No, it doesn't look legit to me either.