Hey Raj,
Eon has 814CC engine displacing peak power of 56 BHP and peak torque of 76NM
For the rumour of vibration in Eon - the best answer is take a test drive and feel the car in different speed pick up
Having said that - You cannot expect to drive a smaller engine car with greak pickups too - There is sure a gap when you speed up to overtake the car - if you compare with I10 or Swift - they got bigger engine 1.1 Litre and 1.2 Litre - also has better power and torque
On stand alone basis - Eon is a descent car with host of features, infact one of the top 5 selling small cars in India. Take a test drive and feel the drive.
Read the comparison below
Hyundai Eon Vs Alto K10