The Riverbank Bentota is an excellent guest house. The rooms are large and comfortable, and the Wi-Fi worked well during our stay. There is a pool, which was most welcomed in the heat. The included breakfast was very good, and the family also fixed us lunch and dinner (at modest additional cost) when the local restaurants were closed due to a holiday. They also gave us complementary rides to the beach (about 1.5 km away) and provided a convenient ride to the airport at the going price.
The local area is not as nice, as the guest house is on a busy street, with many shops and a market mostly used by the locals. The large tourist hotels are across the river (about a 15 min walk). There are limited restaurants near the guest house, but we found the Happy Fish Restaurant (next to the bridge across the river) a good choice.