We currently use fraudrecord and maxmind. Just make sure you submit all the variables for better matches. One match doesnt necessary mean it's the customer in question unless it's the email address. But then again fraudsters just create new emails when they register to bypass fraudrecord.
From experience be careful of customers who sign up for many accounts after the first one is activated especially from Brazil.
If they paid with paypal make sure the email on file and the paypal email are an exact match. We usually request CC verification if maxmind is higher than 50.