Just returned from a holiday at the Kalidonio. Booked on line with Direct Holidays with free child place and £80-00 on line discount.
While the apartments were typical basic standard in Greece (no shower curtain, no kettle but did have fridge and small stove). They were very clean and comfortable. Staff very friendly, poolside bar swimming pool good. Breakfast and snacks reasonably priced.
Location on a quiet dark road half way between beach and main street.
There is no entertainment but other hotels welcome you to Greek nights, Sky sports and films.
Excursions booked on the main street were cheaper than through tour rep. Eg. Boat trips 13 euro. rather than 20 euro.
Best restaurants to try Mermaids and Pathendos (Ithink thats what its called!)
If going again with kids I would try Hotel Venus or Siccoco.

P. S.
In answer to Lu ce, nearest bar was Iguana, small sports bar or Drunk Corner a few mins walk.
Nearest restaurant Escape (if you dont mind the cats wandering around your feet) food nice, served in small garden or inside.

Not much going on for teenagers apart from pool tables and TV shows.
Pedalos on beach but no water sports.
Smugglers Cove boat trip not good value but Island tour by coach was. (additional charge for caves boat trip 7 euros - worth it).
Eurozante coach rep very informative. But meal at Taverna not very nice.

Visited smugglers cove on the Delfini boat out of Zante harbour.
Booked through Direct Holidays rep at 20 euro per adult 10 euro per child.
No offical rep on boat apart from an English bloke who gave the odd comment and the greek captain Spyros who we couldnt understand.
Although the sea was rough at times, we did get to land on the beach before the other two boats came in. Then the beach got crowded.
Very hard on the feet at the beach was very pebbly.
Bacon sarnies and hot dogs were microwaved and expensive.
To see the Blue Caves, its best to go by small boat (part of the island tour) as you get to go through the caves and get great photos.