We stopped there for a couple of nights (22 and 23 March), and although it's a very untouristy border town we still enjoyed wandering around the place.
Took a tuk-tuk from Poipet to the Market Motel in Aranyapraphet @ 80 bahts.
Booked one of the best room in the motel @ 550 bahts, and had a very pleasnat couple of days.
Breakfast wasn't included, but the semi open-air restaurant/bar was reasonably priced, and the swimming pool very welcome.
We caught the 0640 3rd Class train back to Hualamphong, and the train journey was one of the highlights of our trip. Ticket was 48 bahts each for the 5.5 hour journey.
Well worth breaking your journey if you're not in a rush to get back to BKK or wherever.