My initial review is positive. I played for about 4 hours with 1 coop buddy and got to about level 9. One single crash the entire time and my fps remained at 144 which is my vsync value so I didn't get the performance issues people seem to be getting.
It still has claptrap being silly and that form of humor, but the other characters are not unintentionally annoying which is my biggest complaint with 3 and the spinoffs. All of the spinoffs and 3 had terrible dialogue.
It has more violence, I don't remember as much blood or realistic death, in the past everything was very cartoon-violence.
it does have it's own general on the board so I'll talk about it there instead of here but just wanted to follow up with my post from when I started playing earlier today. I don't think I would advise anyone to rush out and pay the full sticker price, but this actually does feel like a fine coop game and a fine looter shooter and I personally think it's better than 3 and all of the spinoffs, so it's a fine installment in the "I'll grab it on sale, or if my playgroup really want it" list.