I point all our domains to CloudFlare. This way, I'm totally registrar independent, no need to login and fiddle with numerous registrars' very different CP's. Not to mention CF's add-on functions and DDoS protection, should you avail yourself of them, free of charge, I might add
Needless to say, I'm not a fan of Efty's instructions to point domains to their nameservers. No thanks! All you need to do is set each domain's record "A" to Efty's webserver IP address (currently 119.81.170.18) and voila! Domain's at Efty, but you retain full DNS control and can fiddle with all DNS records - including MX's, SPF's, TXT's - to your heart's content
EDIT: you can keep your domain pointed to one set of nameservers and therein point subdomains (e.g. www) only to other nameservers (i.e. Efty's). All other records (e.g. MX) remain under your control on "your" nameserver. I don't think you can make that work with the main domain record, though.
Disclaimer: works like a dream, but it's a hack, not Efty standard protocol. Nothing stopping them from moving stuff to another box or changing the IP address and all your domains stop resolving.