I'm about 6 hours in but running out of steam with this now, not sure if I'll go back.
I got to a point where the boss I need to fight is too tough (a robot spider that many people seem to rate as the hardest part of the game). So I've gone off on side missions to level up a bit, but the return journey from one of these quests is huge and full of hundreds of enemies. I'm just bored of fighting them, it's relentless.
The map is not much help for finding the way back to the quest giver, and the fast travel taxi option only seems to work for areas close to where I am, I can't use it to travel home.
At this stage I would certainly use a cheat to give myself all the weapons and upgrades, since it isn't really an RPG or adventure - it's a full-on shooter, and the way you upgrade your character early on can make it hard to damage some of the later enemies. Shooting games are way more fun when you've got a maxed-out arsenal.