After living in Kailua for several years, I can truthfully say it's one of the best cities I have ever lived in. For starters, Kailua is on the water, which means there are tons of options to choose from regarding water activities. Kayaking, paddle boarding, and just relaxing on the beautiful beach are just a few options. Go on the three peak hike or visit the Lanikai Pillboxes for some amazing views.
If you are moving with kids, Kailua has some great schools, both public and private. Most schools are located in the eastern part of Kailua, which can be a little tricky if you don't live in the eastern section.
Shopping in Kailua is mostly artisanal, small scale businesses, as community is a big art of the culture here. Restaurants are all over the place, with delicious cuisines.
The biggest downside to Kailua is the price of real estate. With a median home price of $918,000, Kailua is the most expensive city in Hawaii.