I can't really compare having never burned ant, but the bit I'm burning this year smells like coal outside on reload, but doesn't smell of sulphur hardly at all. Yes, my coal does smoke for a few minutes after a reload, but 20 minutes in here's a worse than usual example of what comes out the stack:
Bit stokers burn even cleaner than that with regards to smoke. Neighbors that pass by have asked me why I quit heating with wood as there's too little smoke once the vols have burned off to be seen from the road.
As to being dirtier, my coal isn't washed when I buy it (Bulk) so yes I suspect it has a few more fines attached to it than bagged ant. However, between buying it & loading it into the stove most of the fines stay outside or in the bottom of my scuttle. Overall my stove area is MUCH cleaner with bit than it ever was with wood.
I haven't had any real issues with soot despite the fact that I'm running 6" class A chimney. The only time I've had soot issues was when I was using fines, now that I screen better I've had no buildup to speak of.