Hey, if you're considering the purchase of Season Six, I am sure (at least I hope) you have seen the first five seasons, and you liked the first five seasons. I got hooked early on when Showtime had a free preview. I didn't get a Showtime subscription but I did purchase Season One.
Well, this is Season Six. That should pretty much explain it all.
I would not suggest getting Season Six as a standalone purchase. You could watch it but I think this is a case where watching the series in order helps--kind of like The X-Files in that way, but this ain't no X-Files.
The series is an acquired taste. I love it. My wife: meh, not so much. Our taste in music differs, too, so c'est la vie. I like Warren Zevon.