Pros and cons to "new work" box vs junction box with mud ring in new construction

Question

Putting drywall on studs, I can add switches and outlets using New Work boxes that stick out from the studs or I can use a plain junction box and add mud rings. Are there any pros or cons?

For me, the biggest difference would be that with New Work boxes I'd have to develop the skill to accurately cut drywall to fit. I know of several techniques but they all require practice and experience. Cutting it after installation from inside a plain junction box seems easier.

Answer 1

You must install the mud ring before fitting drywall, so it doesn't buy you any advantage there.

The biggest advantage of mud rings is they are typically used with 4x4x1-1/2" steel boxes, and that means, you have a very shallow box. 2 such boxes can exist back-to-back in a 2x4 stud wall (and with a conduit nipple pass-thru between them) which means

1. the boxes are more sturdy with the pass-thru giving strength.
2. switches can be back-to-back with no need to offset them.
3. it plays well with my preferred wiring for receptacles, which is to run 1 cable down the wall and feed rooms on both sides. 1 circuit per wall (coarsely) and now each room has access to 3-4 circuits (shared). So the "home office" room isn't starving for power.

Answer 2

Having installed a few of each now I'm going to answer with a huge vote for mud rings because:

1. You can use a box one gang larger than you need and a reducing mud ring, which provides lots of space to work and moves the devices away from the cable entries and the box's ground screw. (You can do the same with an oversized new work box by adding a blank position intentionally).
2. You can adjust the mud ring slightly -- up, down, left, right and rotated in the wall's plane so you don't have to worry as much about the box being perfectly aligned when installing it.
3. It's much easier to mud a tight seal between the box and the wall void with a mud ring, which helps with reducing noise and dirt in the finished product. And your drywall cutout doesn't have to be quite as perfect.
4. The mud ring provides a strong backing for tile, especially small or mosaic tile, right up to the edge of the opening so it's easier to install the tile and easier to install the switches and outlets without breaking the tile.