While I agree with not locking yourself into one company for a lot of services, I'm not sure that using a third party DNS server puts you in a better position. The Namecheap servers were knocked offline by a DDoS attack. Do you believe that third party DNS servers are more resilient to that type of attack? At least with a registrar provided DNS server, you're a paying customer and so you can probably expect some form of customer service that you might not get with a free offering.

CloudFlare is probably better set up to deal with that kind of attack because they have a paying customer base and specialise in resilient website operation, but whoever you're with, if a DDoS is big enough it'll be hard to protect against.

Amazon Route 53 is $6 per domain per year and they have a whopping 26 anycast locations and 100% uptime SLA.

Just in case you ever want to backup your Route53 records... https://github.com/Hack56/Route53-To-S3

Tnx. Another option is ClouDNS, they're also free (for up to 3 zones)