i5 3570k worth it ?

Please bear in mind not all are built equal. I bought mine second Hand and it can't get higher than 4.3 without ridiculous voltage. Some will do 4.5 just on stock. Id say given prices in your area it's still a good deal as mine does absolutely fine in all games, however don't buy expecting to get a guaranteed 4.5+ out of it. Might be lucky, might not. Also depends on motherboard, power phases etc.