My only experience with MaxMind was the trouble we had when we got a new IPv4 assignment from ARIN. I filled out the form on their website the first week, our address was in the WhoIS records for our IPs, and our BGP announcements made our location obvious, yet they had our IP's (obviously from ARIN) showing up as originating from South Africa for months.

Seems like anyone who can look at BGP tables and whois information can get more current and accurate data than MaxMind.