I'm currently 3 hours in on my Fubar playthrough. I managed to make it to chapter 10-2 (the part when you are on the side of the truck with the grenade launcher). So far Fubar hasn't been to difficult for me, but I'm pretty good at games in general. Some tips that have helped me in bullet point format:
-417 assault rifle: This gun is amazing. 1 shot to head on most enemies with 2-3 shots to the body. It also has a 4x scope, use it.
-Let your teammates do a lot of the killing you can't do. You kill the guys that you can kill, but let your teammates take care of the ones who are in a position to kill you. An example of this would be enemies who are elevated above you. Instead of popping out risking to take him out, utilize your team.
-When stuck in a situation, change up your strategy. I remember early on, I think it was chapter 5. I died like 3 times so I changed up my plan. Instead of guns a blazing, I spammed my grenades to get the AI to dive or get stunned. Then I picked them off.
-Take your time. There is no rush so stay behind cover for 10 minutes if you have to.
-When aiming with LT, clicking in the right joystick changes the angle of which you can hit targets at. Utilize this feature.
-Popping out of cover to shoot someone is not always the best idea. Rather detach yourself from cover and then crouch. Slowly side step out of cover to pick off the enemy and then side step back. Normally when you pop up you can get hit from multiple angles. When you do the strategy I just mentioned, the only person that can hit you is the person you're picking off.
Using these strats I steam rolled through chapters 1-5 in a little over an hour. It's taken me 2 hours to do 6-10. When I wake up I'll finish off the game. I know that chapters 13 and 14 are probably going to be a bit tricky. Keep at it gents, you'll get there.
One last tip. I noticed that when you don't move up, your teammates don't move up. They normally only advance if you tag someone or if you move up. They will sometimes move ahead a little bit, but never to far. Keep this in mind and try to pick out most enemies from as far back as possible so you don't have to deal with your teammates dieing all the damn time. GOOD LUCK!!
Edit: I wanted to add one more tip. I can't stress the importance of vantage points. Always look for the best spot to place yourself for the duration of a fight even if you have to die a few times to find that spot. Once you find a good vantage point then things become a lot easier. Only advance when you're SURE all the enemies are dead or nobody can hit you. We are talking about 2 shot deaths so take your sweet time.
Update: I started playing the game again when I woke up now I'm on chapter 14. Chapter 13 wasn't too bad, but I can see how some people are having trouble on it. Chapter 13 was all about having optimal points for me to have to pick people off. The weapons I had on me during Chapter 13 was a 417 and either an M4a1 or a scar. I definitely died the most on this chapter, but I got through it in under an hour. I wish I had a capture card. I would post walkthroughs on how to make it through. Right now I'm on the middle of chapter 14. I'm at the point where there is a big battle with 2 turrets and a bunch of soldiers. It's the big battle right before the Juggernaut that Walker envisions as Lugo. This part seems to be the toughest part for me because of the damned turrets, so I decided to take a break. I'm currently 4 Hours and 35 minutes exactly in on my Fubar playthrough. I'll update once again when I beat the game.
Final Update: I finished the game and cleaned up the few remaining achievements I had to do. My fubar playthrough clocked in at 4 hours 48 minutes 44 seconds. That's not too long considering my suicide playthrough took me 4 hours and 46 minutes. As for some closing remarks, just keep at it and you'll eventually overcome this game. When you start to get frustrated, take a break and comeback to it. You'll do better the next time you come to it. Also, TURN ON AIM ASSIST. I did both suicide and fubar without aim assist because I didn't know it existed. I probably wouldn't have turned it on anyway due to pride issues, but that's besides the point. I cleaned up my remaining cheevos on easy and aim assist was automatically on. It made the aiming MUCH easier. If you get stuck, don't hesitate to use aim assist. With that said, I'm sending this game back to gamefly. If anyone needs some tips feel free to message me me here or on XBL. My gamertag is lilsting.