mythdora is fantastic.
i installed mythtv in dual boot mode with mce - i had to lose mythtv unfortunately after the missues started wanting to watch tv giving me no time to setup myth
the main issue with linux is the drivers and getting them all to work together. mythdora has all the necessary kernel mode modules for a wide range of tv tuner cards. previous to this you had to compile and build them yourself. the compiling and building wasn't so bad, but if you're device wasn't supported (i.e. my hauppague Nova-T 500 on an old 2.6.18 kernel circa Fedora Core 6) you had nothing... and had to wait for a kernel update (which is okay on fedora) or compile the module yourself from source.
configuring the back-end and front-end is so much easier now it's great. the open source codecs and mpeg2 decoders have been tweaked and optimised by so many people that they are comparable and even equal to many commercial mpeg2 decoders/codecs. Just check doom9
