DNS is easy, mostly. Most users just don't care about DNS, so they use their domain-registrars' offerings (which are frequently terrible). The people who do c

DNS is easy, mostly. Most users just don't care about DNS, so they use their domain-registrars' offerings (which are frequently terrible). The people who do care seem to pick their provider based on either price, or on features such as non-standard record types (the various different hacks to allow top-level CNAMES, or the ability to return different results on a GeoIP basis.) Once you start relying on these special things moving becomes hard - because different providers either don't offer them or don't offer them the same way.