Where have you been the last 7 years? You should start from season one. Great stuff.
I first saw part of an episode about 5 years ago. Thought it was interesting but never watched. Then a year or so ago I watched a rerun of the season premiere of season 4. I thought it was good but didn't follow up. I then saw it appear in Netflix instant and dragged my actually starting it but once I did I blew through it in 2 or 3 months.
If you like the X-Files you will probably like this. It has monster of the week episodes and instead of a running alien mythos storyline there is running demon storyline that pretty much evolves into a season or two storyline.
The show is pretty funny a lot of the time. There is awesome pop culture references to movies and music and if a storyline is "ripping off" a previous notable work they often joke about the source material. I thought seasons 1-6 were the best. I found season 7 to be a let down. The Leviathans were kind of lame and so were their plans. Plus they hardly used Castiel who had become a break out character...what the hell are they thinking. Plus i felt thy offed one too many support characters which could have made season 7 a bit stronger.
They also sink up some good classic rock songs to scenes in the show pretty well most of the time. Styx Renegade, Dylan's Knockin on Heavens Door, and Jefferson Starships Miracles were some of the best. The last had an in episode joke for even using Jefferson Starship and the song fit well with the big reveal at the end of the episode.
Definitely some funny stuff like the Deliverance references in The Benders episode. Castiel's dead pan cell phone problems, to Deans comment about cherubs, and the episode where he watches porn were great.
Oh yeah and the last episode had Thor's Hammer. I kind of wonder if Sam kept it or it will simply disappear and be forgotten. It would be a good time for Thor to finally make an appearance on the show since Odin and "Loki" already appeared.
I pretty much agree with everything you wrote.
The show started out with them killing off the monster of the week, but has gotten much better with the larger story lines surrounding angel politics, the absence of God, the rise of demonic forces, the control of earth, the needs of the many outweighing the few, etc.
The show has a high testosterone count. It's definitely a "guy show," as compared to Vampire Diaries which is clearly written more for a female audience.
It is also very clearly using the Batman mythos, re-imagined with strong biblical and pagan underpinnings though a Gaiman-esque lens.
Dean: Batman
Sam: Robin
Sam on his own: Nightwing
Impala: Batmobile
Bobby: Alfred
Bobby's House: Batcave
Castiel and the angels: Gordon and the police
Crowley: Joker?
Parents killed by forces of evil
etc., etc.
Add rock soundtracks, cheeseburgers and pie...what's not to love? It's easily one of my favorite shows on TV.