Most people here aren’t really big fans of them. Personally, I prefer an uninterrupted counter, and the busy-ness of the two (different counter heights being cut in two by the backsplash) isn’t my style.

Having said that, I believe the recommended overhang for a raised, bar-height seating is 12”. I would want a standard counter depth (~26”) on the lower portion.

Yes, have a normal working depth on the kitchen side and size the higher one based on if you want people to sit there.

Pros are: (1) you have a place to put electrical outlets, turned sideways, in the vertical wallboard of the raised area; (2) the higher bar area can hide some kitchen messiness from the great room or other open-concept area. The cons are: (1) I think most people feel like it's out of style, depending on your layout and what else is happening in the space; (2) it can feel like a barrier/feel crowded, both visually and physically, again, depending on what else is happening in the space.

Another con is that bar height stools are harder for small kids and older people.