In days gone by, the 744 was regarded as the very senior fleet, with ALL the good routes. However the -400 picked up a lot of the Classic work and in turn lost some to the 777, meaning that the two fleets now are pretty close to each other in seniority terms. -400 work is now based around the US, Africa, India and Far East/Australia, whereas with the 777 you will get east coast US, Caribbean, South America, some Africa, and Middle East with exceptions such as Beijing.