1

We stayed in a small village of Kvariati, between Gonio and Sarpi. The water was clean, the house that we stayed in right next to the beach (as are most of the houses in the village, which is squeezed between the sea and the mountains). If you want a quiet place, Kvariati is recommended; if you are into partying, other places are better.

There are several direct marshrutkas from Batumi to Zugdidi. If the times don't suit you, you can also take a more frequent marshrutka to Poti and change for Zugdidi there. The direct marshrutka takes something like 3-4 hours AFAIR. Taxi would be faster but of course more expensive. Ask around the bus station when you arrive in Batumi and choose what suits you best in terms of time & cost.

2

Completely agree with # 1.

Kvariati, Gonio and Sarpi have the cleanest beaches. But with pebbles, not sand. Ureki has magnetic (blackish) sand, but water there is not as clean as above-mentioned ones, but quite decent though for Georgian standards. Batumi and Kobuleti are better for their nightlife, but definitely not for beaches and clean water.

3

For me Batumi is the best. In summer that is full of tourists, because it don't need to have big budget for the vacation in Batumi. You can take accomodation or small budget hotel: www.hotelsinbatumi.com/