So my questions .....
Are they now considered a good safe idea without routers overheating etc?
Are they really effective for edge work?
Are the Incra Cleansweep rings necessary for a dust box?
Will other rings (woodpecker) with large openings work just as well?
Is a side dust port and opposing air vent better than bottom dust ports?
Basically what is the general consensus on dust collection boxes?
I don't think overheating is a problem so long as you are using dust collection. The amount of air being sucked through keeps the router plenty cool. The vents on the side helps in situations where the hole is mostly covered as when routing dados.
By themselves I don't think they would be as effective as when used in conjunction with through the fence suction, but if you leave big enough of a gap around the bit you should get the majority of the dust, although there is always some wood chips that get shot across the table.
I have plastic rings on my table and drilled some extra holes in them to help with dust collection and it helps. I think it is a better option then increasing the size of the opening in the ring.
The problem with big openings around the bit is the workpiece getting caught on the lip of the hole. Generally, I try to keep the opening as small as possible just as I do the opening in the fence.
I have two of the Rockler ones. They do a fairly decent job emptying the sawdust although it seems to leave a small amount in the corner blocked by the cord. Don't know about the Incra.
In woodworking there is always more then one way to accomplish something.