Metal anti-static wrist band better than fabric wrist strap?
The point about static electricity is that there's usually not that much energy, i.e. charge, building up over a short time.

Therefore, a couple kOhms resistance don't make that much difference - your body voltage would break down over that.

I'd argue that the fabric ones are better for most usage scenarios: they are simply more comfortable to wear, and that makes a difference in usage, and also, humans become sloppy over time – and that'll lead to you being more likely to take off the wristband "earlier". 


  Is there any change of static build up on the insulating outside of a stainless steel anti-static wrist band?


I'd say: no. Not at all. Ok, it depends on the conductivity and thickness of that lacquer, but assume the following. I'll try to draw a worst case scenario.

You take your angora bunny to your workplace.



For some reason, that bunny gets aggressive/bitey when you don't pet with your wrist, so you pet it with your wristband, and by doing so, you're constantly stroking with the outside of your wristband.

Charge builds up on the wristband's outside. However, that charge is either very small, or directly discharges into the metal part.

So you're fine.

Someone notices you and your pet rabbit at work and fires you, but not without offering the position of chief rabbit safety overthinker in his night-time job, organizing rabbit fairs. You become famous and rich.



Not that bad for a worst-case scenario.