When I was small, eating out at Zippy's was a treat. You didn't need to dress up, the atmosphere was very casual, and, best of all, Zippy's offered large portions of local favorites at prices that average person could afford.
As the years have gone by, I've noticed that the casual ambiance is still there, and they still welcome you even if you're wearing t-shirts and slippers. However, their prices have been constantly on the increase, while it seems like portions have either remained the same or shrunken slightly. A lot of the lunch or dinner plates are above $8, with many exceeding $10 if purchased as a "complete meal." At that price range, there are numerous other choices in Kailua.
Parking at the Kailua location is terrible, with a limited number of narrow stalls and an extremely narrow aisle. The u-shaped lot also backs up when the drive-through take out line is just a couple cars deep, so be prepared to get stuck in a mini-traffic jam during busy hours.