Juggernaut has a total of 157 million recorded matches, so it's not that far ahead of Invoker.
Juggernaut has 3 active spells and 1 passive spell. Since two of the active spells are fairly straight forward, he is a relatively easy hero to master. However, make no mistake - he's still a very rewarding hero to play. It's quite simple - no matter how far in the game you are, if you happen to find a single enemy away from any creeps, it's an almost certain kill, thanks to Juggernauts powerful ultimate!