If you do pick it up, Pick up GOTY edition. It has all 4 DLC's (Captain Scarlett Pirates Booty, Mr. Torgue Campaign of Carnage, Sir Hammerlocks big game hunt, Tiny Tina's Assault on the Dragonkeep), Both characters (Krieg, Gaige) The first level increase, Creature Slaughter dome, Character skins, and the Premier Club pack.
That's a
lot of game right there. I'm just estimating here, but this is how many hours I think you could get out of that DLC if you did
everything once, without getting stuck anywhere, with each character:
Normal playthrough: 15h (my first was over 24 hours but second was 10h)
TVHM: 18h
UVHM: 20h
Total vanilla game play time: 53 hours
DLCs (I don't think I've 100% completed any of these yet so these are rough guesses, also only counting one playthrough of each, not one playthrough at each difficulty level (which is possible)):
Captain Scarlett: 7h
Torgue: 7h
Hammerlock: 6h
Tiny Tina: 8h
Digistruct Peak: First run, according to YouTube walkthrough video lengths, 45m. The last (8th) run would be more than that but I don't know how long, so let's say an average run through of 1h, total of 8h.
TK Baha's Headhunter pack: 45m, excluding the secret other boss.
Total play time with one character: 53 + 36h 45 = 89h 45m
And as there are six characters, that's about 538h 30m.
In real life there's far, far more than that; I've done about eight normal playthroughs, seven TVHM, three UVHM (and I reset one of those completed runs), Captain Scarlett once all the way through but not 100% complete, Torgue twice (also not 100%), Hammerlock not even once all the way, Tiny Tina once and a half, I've never even been to Digistruct Peak and I've done the Headhunter pack boss once (but not the secret boss), and I've been playing for a hair under 587 hours. I have spent a fair amount of time grinding badass challenges, though, and farming. Oh yeah, farming will easily add a good few hours.
So if you love the game, you get so much for your money. The thing is, lot of people I know didn't even finish one normal playthrough!
Edit: So I killed Rouge three times today, once I just got the Skullmasher and Baby Maker, the subsequent times I also got a Hydra, so that was nice... I considered farming it all night but frankly I can't be bothered, I've got a lv70, 71 and 72 'masher now so I might respec Zer0 for sniping as he approaches the cap. As unlikely as it is, I really, really, really hope Gearbox make the Cobra a loot hunt drop, my lv50 one is great and all but I want a better one... Same goes for the Order.
This screenshot shows the shield I had been using from lv61 to 72 compared to a random common drop I found in a Skag pile. Yeahhh. If I can't find an Order, maybe I should make it a Love Thumper or just any epic roid shield. Or, if I can be bothered, a Hide of Terramorphous...