[Wlug] MythTV vs. Tivo

So I've been thinking about picking up a PVR card and turning an old machine I have lying around into a MythTV box to replace my tivo to get rid of that nasty monthly fee. Does anyone have any comments on the comparisons between the two? Will I miss my tivo? Does mythtv have equivelant options for season passes or recommentations? Thanks, -Marc