For Sri Lanka in November I had a great stay at Amari Colombo right in the heart of the city and used it as a base to explore a lot around the island.
Even though there was severe weather in November this year it has all settled now and everything is operating normally. Sri Lanka is beautiful this time of year.
I recommend spending a couple nights in Colombo itself to see the waterfront, Galle Face Green, quirky cafes in Cinnamon Gardens, and the National Museum. Then head south to Galle Fort for the old Dutch ramparts and boutique shops. The beaches around Unawatuna and Mirissa are perfect for relaxing and swimming. If you enjoy nature and waterfall Ella and Nuwara Eliya in the hill country are breathtaking with cool weather, tea plantations and views from Little Adam's Peak. For wildlife try a safari at Yala National Park.
Amari Colombo made it easy to plan all of that with great service and a central location.