DotA 2 Top 10 heroes and Top 3 Bottom heroes:

Top 10 :

10. Riki - High Agility. Can be very OP if you Up Agility
 9. Traxex - Powerful in late game.Will do many damage if you Up Agility
 8.Warlock - Attacks are powerful and does a lot of damage
 7.Sniper - Assasinate is very good, does many damage in long range
 6.Batrider - High movement speed, very powerful.
 5.Krobelus - Silence is very useful,Withcraft is a booster and can highly improve his skills
 4.Enigma - Low mana, but ultimate can turn game around
 3.Juggernaut - Moves are great for getting kills and last hits
 2.Void - Chrosphere are great, Time Lock is also good when upgrade it
 1.Lich - Ultimate is very useful, good mana supply and damage

Top 3 Bottom List:

3.Morphling - Almost no damage done, bad moves
2.Bane - No damage, SUPER LOW MANA POOL!
1.Meepo - So hard to use it!!!!!