I really enjoyed it. Both online with friends and offline. I probably spent more time offline than online.
I did need a friends help though to fight a couple of bosses. ;3
It's my second-most played Steam Game, and was my most played for quite some time, at 174.0 hours on record.
That was recently taken over by Mount&Blade: Warband at 182.8 hours, though.
I haven't played it in some time, actually.
I last played it probably almost a year ago, actually, near the christmas update. I should get back into it. It was a lot of fun.
I'm not too surprised with the cost, actually. It's only £5.99 on Steam, and I got it for about £2.95 or something very similar when it was on sale once. I've seen it in my local Game shop too, but I can't recall the price of it. I think it might have been something stupidly expensive compared to what I paid.