1)it depends on what era of the midle ages- the late middle ages, the armies of medieval europe were actually starting to get group disiplne, and use real tactics, other then th eold line 'em and charge
2)that said, an early medieval army is mincemat- the Roman army was not some static fomation where everyoen was armed the same thing, if anyoen here belives tyhat the Romans went into every battle with 2 pila, a short soward, and what ] not, then they dont have a clue as to what they are tlakign about
-records are quite clear- generals armed thier troosp with what they needed to succedd- Ceaser is knwon to have armed his troops with pikes, Trajan to have made his legioanries into osmthing as heavy as later medieval foot knight
-I wont let any oen heare continue the long held assumption that Imperial cavalary was crap- it wasnt, pure and simple- they used the same type of equipment, but had better tactics, and it was late Roman cavalry which provided the basis for th e knight, the germanics lent thier semi-feudal heirarchy to it all, and you get a noble trooper
-lets nto forget the assorted styles of ballistae. soem of them as large as a modern day rifle, and were for all intents and purposes, a fancy type of crossbow
-The Romans I woudl say would be by far the more competent amry- all of its troops were trained, regimented, well equipped, and knew thier duty- of the middle ages, only the nobles woudl have such a veiw, while the mainstay of the amry -the foot men- woudl not have, them being a mixture of the peasntry, and mercenaries