Can anyone tell me what the difference between the header coatings are?

I like the silver smooth finish look, I believe it's what Tony has on his headers.

Is it worth having old used pipes coated, or should I wait till I use new pipe?

What to go with

Jet Hot
HPC
is there a better brand???

 

I would wait till you got new ones. What ever is under the coating may start to grow again.
I believe mine are the Hooker Thermal Barrier Coated Headers.
Smooth Metallic Ceramic Coated inside and out.

 

You are better off waiting untill you get your new ones. Mine where coated by Jet-Hot, inside and out , in February of this year

 

NICE!!

thats what I'm looking for.