Sri Lanka is a beautiful country, the glimpses I got in 4 days. I went through a holiday planning agency called ' Aitkenspence', the agency made the trip completely hassle free for us. :)
1) Travel company - ofcourse I missed out on the beauty of exploring the country by myself using books and other learning resources, making umpteen number of itineraries before finalising and most importantly getting to know all our hosts. But considering the fact that I had just 5 days before flying to Colombo, this was the best option. convenient, comfortable and recommended - if you re not the kind of person who plans a holiday for 2 months at a stretch :)
2) Weather in Aug - It was extremely hot during the afternoons in Aug
3) Food - We had most of our meals on the restaurants by the high way, these are very different from India. The restaurants are on the road, almost always serving home made buffet.
For vegetarians there are sufficient number of options - dal, different subzis, powered coconut (Spicey), hoopers etc (i have attached an image of a typical rice meal, this available everywhere in Sri lanka)
4) Guides and tickets - Tickets to every tourist spot are extremely expensive. They are almost 40 times the price that a localite pays (for SAARC nations) (you can get the exact details on the internet) - entrance tickets to some of the places we visted were close to 1000 INR per head