It IS a long day, with ~11 hours of the trip being on a bus travelling to and from Washington DC, but you get to see all the main points of interest. We were lucky (or unlucky) that the weather was pretty drizzly so it wasn't busy at any of the parks or buildings. There's plenty of time to take your photos but each stop lasted about 10 mins so if you're expecting an opportunity to stroll around to take it all in, then this tour is not for you. I was quite happy at the pace.
Our tour had a family that spoke Spanish so our tour guide was providing both English and Spanish - information was informative and if you had questions about certain landmarks, she was more than happy to provide you with more information (you just need to ask!). Lunch is later in the afternoon, just after 2pm, but you have an hour or so to eat and explore one of the many museums including the Space and Air, American-Indian, and National Art Gallery (the latter which I would recommend).
The journey back is long, we left about 3.30pm and didn't get back into NYC until 9.30pm (traffic is pretty much stop-start from Washington until you pass Baltimore). Again, if you're short on time and just want the photos with some brief history, this is ideal, however for anything more in-depth, you'll need a couple of days in DC to get that.