Hey,
as I am owner of a Mac for a month now, I am also looking into the iTunes Store. And some series are cheaper than the DVD , which you can buy in a shop for example.
But I am sceptical! I know the methods how to burn bought iTunes-movies/series to a DVD, but is the quality good enough to watch it on TV?
I am interested into Married...with Children ( or as it is called in Germany: Eine schrecklich nette Familie), and of course it is only SD, i don't have problems with it. But yeah, I don't want a "bad suprise" when I put the DVD into my player (low quality , wrong format , etc.)

I'd think that iTunes movies would be higher quality than DVD video, at least if you buy the [HD] versions...

Watch the trailer, I think that would be around about the quality of the film.