shaco is my second most played champ with a 67% WR, and yes his early game is tough to counter. wards do nothing against him b/c i just run up the lane 80% of the time. I shut the opposing jungler down very hard more often than not generally control the first 20 minutes of the game.
BUT THAT'S NOT THE WHOLE STORY
His strength lies in creating advantageous situations rather than just being a high damage/tanky brawler, and when the enemy team groups up, all he can really do is split push. He can teamfight, but he either needs to play cleanup after an even fight, or try to assassinate a carry. with a decent cc support and/or ezreal, he'll never be able to kill the support before he dies, so basically he serves to zone the enemy support and carry for a few seconds. And while that is a contribution, it's sub par and only really a decent plan once you've knocked down all t1 and t2 towers.
In short, yes his early game is strong, but he needs it.