if you know how to use the hogs, jets and longswords, you can get anywhere easly.
the marine dropship is quite bugged... it was meant to fly, not to drive in circles on the ground.
the ghosts are more used for safer transport, hogs for fast transport.
longswords are offensive, mythos (which called a mech actualy) are defencive. longsword's nuke is maybe strong, but its quite easy to escape if the longsword himself isnt in the range.
jets are for fast transports, and snipers supposted to stop them. they not better then rifle in close fight and you can be killed quite easy becuse you are on foot.