We are not ones who normally do package tours but are more independent travellers and don't often take guides even in the most remote of places. In Sri Lanka, having a driver like Dumi (as he will tell you not DUMMY) made the week effortless despite some marginal weather many of the days.
We were picked up from our Colombo hotel promptly at the allotted time. There was a little bit of confusion as I didn't get the driver's name in advance, but we quickly sorted that out and were on our way. The car that was used for our week was very comfortable for longer drives (we had a few days where we spent a fair amount of time in the car).
If you are pondering a self-drive car (which is what I normally do) vs. getting a driver and car, I'd strongly recommend to get the driver in this case. Having the driver avoided any arguments about directions or getting lost and with a pretty packed itinerary was able to ensure that we got to do everything on our list.
Dumi suggested things we wouldn't have thought of and got to know the things we liked so surprised us with a few extra temple stops we hadn't anticipated (which is the sign of a great guide). While we had to get additional guides or go solo in a few places, Dumi always provided a debrief on the way which supplemented what was in the guide books. He also made sure we had decent meals throughout our journey (including an amazing beachfront lunch on our last day en route back to the airport).
Sarath provided great communication up front - he was easy to work with and even called the driver and spoke to me at the end of our trip to make sure everything was ok.
We'd definitely recommend using Sarath's services to anyone going to Sri Lanka and would suggest you ask for Dumi for your visit!