First, let's start with the weapons. One of my favorites, and one that was highly profiled before release, is the K9000 Cyberdog gun. To put it simply, this thing spits lead like a mother

er. It uses .44 mag rounds so it definitely does some damage! There is also an upgrade that you can find schematics for that improve it slightly, and add new aesthetics. You'll have to find it in the crater unless you can pass a speech check in the beginning of the add-on. If you have the skill (75 in guns), you will simply be given the gun. Easy as pie! Next, one that wasn't all that powerful, but has other, far more industrious uses is the sonic emitter. I didn't really think it was all that impressive, but you can upgrade it to disable force fields, which not only is pretty neat, but is required in some later quests. You can also find new frequencies for the gun to suit your tastes. The other new gun is the LAER. This one is pretty cool, as it's basically a rifle version of the pulse gun, as far as looks. It's got some fairly impressive stats, but is outdone by some other weapons. There are a few, so you can still repair it if it becomes your new weapon of choice.
There are several new melee weapons including proton axes, protonic inversion axes, scientist gloves, and throwing axes. I didn't spend too much time with them, but I did kill the last major boss with the protonic inversion axe, and it took little to no effort. So, if melee is your thing, there's something here for you, but I think the variety of energy weapons is where the add-on shines. Oh, and quick tip. If you want to make quick work of your enemies, keep the Pulse Gun handy. It will decimate the robotic armies of scorpions in no time!