Nothing much in the city itself,except as a place to review the history of the Indochina War. Aslo could serve as a base to explore around the area.
..beautiful hills and minority peoples.
Very friendly town. Very little traffic, a noticable lack of daytime eateries . Not a spot to expect a lot of nightlife.
The shopping was very good and affordable. We were there in February just before Tet and it was so cool I had to buy sweat pants (4$). only problem I experienced was one old crazy man who hit me with a stick and punched me as we were at a sidewalk coffee shop. He would try the same thing the next two days. I wrote it off to either plane crazy anger or a left over from anger at white guys from previous wars. No harm done but be aware.
Dien Bien Phu is an extremely interesting and overwhelmingly friendly town. We were almost the only Westerners there at the time - March - and many of the locals wanted to have their photos taken with us.
However, if you are not particularly interested in military history, there would not be much point in going except for the fact that it is the nearest place in NW Vietnam to the border with Laos. There is a very efficient daily bus service to Laos leaving at 5.30a.m. It is a local bus so expect locals with chickens, parcels of bamboo and just about everything else you can imagine. The border crossing is easy but takes a little time, however our driver helped us with some of the proceedings. Our experience of the town exceeded our expectations and we were sorry to leave. We spent three nights there altogether.