It's fun for a while, but I became bored after completing it and had no desire to play through again. Levelling up in the game makes no sense, since all enemies level up too at the same rate. So relatively you're always doing the same amount of damage, meaning finding better weapons and gaining levels is ultimately a waste of time. Also there are thousands of different guns lying around but the vast majority will be inferior to what you already have, so you end up making endless trips to the shop to trade. It all becomes a bit of a grind after a while. There's zero strategy- just find the biggest gun you can and shoot everyone in the face. The role-playing aspect of choosing different upgrade paths doesn't appear to matter greatly.
The missions are repetitive- go to x and kill y, or find z objects. Lots of running around across large uninventive maps- all desert & rock. The stupid claptrap robot becomes annoying very quickly with its endless nagging about side missions. The boss battles are trivially easy - very often you can just hide behind a rock to reload and they won't touch you- zero pressure. Or some I just ran and found they didn't want to leave the edge of their territory, or just got stuck somehow, so I could retreat further and pick them off easily with sniper rifle.
The game seems unfinished in some ways, like the designers ran out of money or lost interest half way through. Early on you get some cut scenes between missions, but they soon give up and you're left with text messages appearing on notice boards, like some role-playing game from the 80s. Also you can't really interact with ingame characters in any meaningful way. It's an empty, dead world - quite depressing. The ending is also a real letdown.
Having said all that, it amused me for a time and some of the weapons are excellent, so I would say give it a go but buy it cheap!