You get the EA to work on 10 different accounts with the valerytrading.com purchase (these accounts can be switched on the website if you need it) and 10 different PC/VPS (with no account limitation) in case of the MQL Market purchase. You get both MT4 and MT5 on the valerytrading.com website, but you need to choose only one with the MQL Market purchase. Depending on your mode of use, one or the other may fit you better.