I think Juggernaut works well as a mid hero when you build him like you would an Ember Spirit. Rush bottle to have lane sustain, into Drums and BoTs. This way he is an effective split pusher when using Battlefury's (spell) immunity to TP out of danger. Later build into Battlefury (item) to speed up farming and lastly Aghanim's to be a teamfighting machine. Be sure to abuse pushed lanes using BoTs, and always keep your Omnislash on cooldown.