At some point I want to make a F4T5 preheat fixture and I need your opinions on the ballast, I'm gonna use a Robertson SP48 ballast. There are two listings I'm looking at. A brand new one made in China for 24.95 or a USA made one used with some scuffs for $12.99.

I would say get the used one. Obviously chokes do fail, but not very often. I think a used one will work okay. And it is made in the USA which is nice. Obviously if it is untested you are taking a gamble, but I am assuming you know it works.