At the battle of Hu Lao Gate Lu Bu was About to slay Gongsun Zan when Zhang Fei came to his aid. They fought furiously for 10 bouts. Zhang Fei fought furiously but Lu Bu never faltered. Guan Yu came to help Zhang Fei and several bouts went on again but Lu Bu, once again, Did not falter. It was when Liu Bei joined the fray that Lu Bu withdrew.
Simply Lu Bu is better than Zhang Fei and Guan Yu. But not better when all 3 brothers joined together.
P.S. Read the Encyclopedia
Zhang Fei was worth 10000 men (So it was said) but it only took 2 guys to assasinate him. The God of War was defeated beacause of overconfidence concerning Wu's reinforcements at the battle of Fan Castle.
Please visit this site http://www.theworldhand.com so as to keep it running.
Also try playing this game http://www.darkthrone.com, it might not be the best in the world but it can sure rock.