My first impression; the game starts off a bit slow. You aren't doing much for the first half dozen levels and it seems things open up gradually.
I will admit that even after reading about the game and watching videos on it, it still wasn't quite what I thought it was going to be. There is a slight ounce of reality injected into the combat. You will get the best accuracy when aiming down the barrel as opposed to shooting from the hip, and short controlled bursts more effective that trying to go full auto, which is a bad idea most of the time.
The controls for the vehicles are almost too responsive, I find myself over correcting a lot. I am also struggling with steering; the left thumbstick moves you forward and reverse, the right thumbstick controls left and right steering. My problem is that I want to just control the camera with the right stick and use the left stick for steering, kind of like when you are on foot.
Borderlands reminds me a bit like Too Human. Both games are combat focused, have limited rpg elements in the for of a skill tree, and you get tons of loot which I like. Too Human is more story driven and Borderlands seems more open with you getting odd jobs in between the story, which works for me because it fits the setting.
An hour into the game I was questioning my purchase, but after looking at the clock and realizing that I stayed up way too late playing, I came away from my first time with Borderlands happy. I look forward to trying out some online co-op at some point.