A lot of the issues seem to stem from apple moving from mDNSResponder to a new service to manage networking, discoveryd, which they created from scratch. It could be a while before it's stable.
http://arstechnica.com/apple/2015/01/why-dns-in-os-x-10-10-is-broken-and-what-you-can-do-to-fix-it/
Thank you, I'll take a look.