I have played TQ and just finished up TQ:IT. I have to say it is more of the same, but thats meant in a positive light. Lots of new armor/weap drops (i completed it on legendary)The storyline is a bit weak but its a hack n slash game, i wasnt bothered by the shallow story. I just wanted to kill bad ass boss mobs and there are plenty of them.
I think the average is about 12-15 hrs of play but I always like seeing every inch of the map as i go through so i took my time. I finished TQ:IT in approx 25ish hrs. All in all, i wasnt dissapointed, it was quite enjoyable!