Rooms were clean, comfortable, and much larger than expected. The bathrooms were especially large.
Tube stations in one direction very near (Waterloo - also trains), another just a short walk over the footbridge (Embankment), a third across Westminister Bridge (Westminister)
Red Buses a short walk out to the Westminister Bridge Road and the water bus stop for the water trip out to London Bridge included in Hop Off Hop Off tour deal kicks off just across the bridge.
Aquarium, Florence Nightingale Museum, London Eye, a nice park, Big Ben, House of Lords, a large festival hall (sorry, forgot the name) and I don't know what else right there in walking distance. Also a nice row of restaurants along the river past the park at I think it is called Festival Pier.
Only con I can really come up with, I don't think I would want a ground floor room with a window facing onto the park. If those even exist as I think the restaurant and things like that are on that floor no rooms.
Edit: Sorry, I don't know the current pricing. Prices when we stayed there were exceptionally competitive.