Hey! I've been playing around with Age of Production a bit, and I just replaced my steel furnace stack with Arc Furnaces.
I think this was a major mistake and as is, the downsides heavily outweigh the upsides.
This is mainly because the Arc Furnace's costs are simply too high. I'm running 128 arc furnaces at -80% electricity usage, and they're still outpollution'ing and outenergy'ing my moduled lvl3 assemblers & EM plants. As well as my biolabs, which tend to be one of the most polluting things when fully beaconed. Per piece at -80%, they're emitting 15 pollution and eating 2 MW. The upfront cost of producing them is also pretty high, but that's manageable.
Comparing them to an electric furnace, for 3.75x production (2.5x speed, 1.5x prod), you use 20x energy and 75x (!) pollution. This makes beaconing electric furnaces a much more attractive option - as my current arc furnaces are beaconed... with efficiency 3s, so that I can use a bit of speed in them. But even that isn't enough to significantly outproduce the steel furnace smelting stacks I had before, while being about as polluting (being fully efficiency beaconed!)
I think the idea of their downsides (massive energy & pollution) is good, but it's just a bit too heavy. I'd recommend pulling the 10.3 mw down to 5.3 mw, and the 75 pollution down to ~40 pollution - still much worse than electric furnaces and very rough to beacon, but manageable with efficiency and at least considerable compared to simply importing some calcite and running foundries (which is better for productivity bonuses as well, as you double dip even for plates & its recipes are comparatively faster).
