Both platforms are designed by the metaquotes software company. MetaTrader 4 is the first version which is made by meta quotes software and MetaTrader 5 is a new version and upgraded version of MetaTrader 4. both platforms are good and play a big role in our trading career. we must have a need to learn to do trading in the market. but mostly used is MetaTrader 4 because this is the old and most easy to used that's why most of the traders are used meta trader4.