Yeah it looks good in theory, until you start really using gpg and promote it amongst friends and contacts...
I actually don't really understand the differences between PGP/INLINE and PGP/MIME but it has given me headaches, because some clients don't support both.
Evolution's devs refused to support anything other than PGP/MIME for a long time (seems to be fixed now):
Maybe, but remember that we are the same people that installed/pushed Ubuntu on the computers from our family and friends and gave free support on forums and irc.
We did that because we believed it was a better alternative. So some of us get passionate when advertisements creep in the default installation...
I actually don't really understand the differences between PGP/INLINE and PGP/MIME but it has given me headaches, because some clients don't support both.
Evolution's devs refused to support anything other than PGP/MIME for a long time (seems to be fixed now):
http://mozdev.org/pipermail/enigmail/2010-July/012617.html
K9 cannot read PGP/MIME https://code.google.com/p/k9mail/issues/detail?id=5864