Which side of the island is best on Kauai?
Thereof, what side of Kauai has the best beaches?
Kauai's South Shore offers plenty of beaches, shops, restaurants and other amenities within an easy stroll, especially around Poipu. You're staying at Koloa Landing Resort where there is world-class snorkeling right outside your door and beautiful Kiahuna Beach is just a ten-minute stroll down a paved road.
Regarding this, what side of Kauai is Princeville?
The North Shore- including Princeville, Hanalei, and Kilauea. The East Coast- including Kapaa, Wailua and, in this case, the county seat of Lihue. The West Side- including the towns of Waimea and Hanapepe (It's worth noting that staying on the West Side is much less popular than the other locations)
On Kauai you basically have three main geographic areas to stay: North Shore including Princeville and Hanalei. East Shore including Kapaa and Lihue. South Shore including Koloa, Poipu and Waimea.