The Stronglight A9 is an extremely durable headset. A relative bargin at the price.

I'm not sure in practical terms if you could tell the difference between needle and ball bearings. I'm running the A9 on one bike (79 Peugeot), had one on a frame I recently gave away (84 Trek 560) and on one in the build que (84 Trek 720). If you blindfolded me and stuck me on a bike with an A9 and then a second bike with a Shimano 600/Ultegra HS I'm pretty sure I wouldn't be able to tell the difference.

The Stronglight is alloy. Again, a very durable HS.

Some eighties bikes run a mix of Campy Standard (ISO/BSC) and JIS, using a 30.2 head cup size and a 27.0 race. Check your bike first... I know the Huffy made USA Raleighs often used this mixed HS.