Great with Slardar, Bristleback or Treant protector on your team.

Countering:
Alchemist
Anti-mage
Huskar
Tusk
Lifestealer
Lina
Drow ranger
Juggernaut
Shadow fiend
Puck
Zeus
Silencer
Keeper of the Light
Techies
Necrophos
Queen of pain
Invoker

Beware of:
Batrider
Timbersaw
Slardar
Venomancer
Viper
Brewmaster
Axe
Pudge
Sand King
Abaddon
Phantom Lancer
Sniper
Bounty Hunter
Gyrocopter
Naga Siren
Broodmother
Meepo
Slark
Terrorblade
Crystal Maiden
Jakiro
Leshrac
Dark Seer