Pandy, if you are staying in Ovacik you can probably give the bright lights, topless barmen etc of Hisaronu a swerve by going straight through it on a dolmus or in a cab and down in to Olu, which is a little less brash, but still touristy. Not been to Kefalonia (note to self - must put that right
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) but my gut feeling is that it's nothing like Hisaronu and Olu, but I am sure you will have a great time. It would be boring to do the same things each year and a holiday is what you make it.
Doe