In general, I've found that job priorities, despite having some issues, like this, offer superior performance to previous versions, both in FPS and in dwarven labor achieved in units of dwarven time, with a few exceptions. Jobs of identical priorities at the same location on adjacent z levels cause a lot of unnecessary running back and forth. Use caution with designating the same space to be mined on adjacent levels. Assigning different minning priorities to different levels can more than halve the time to job completion, especially if there is a long walk from central stairwell to job site. Exploratory mining tunnels are a particularly egregious offender.
Another striking issue is that dwarves will not abandon a workshop job for a non workshop job. This means that you can leave hauling enabled on important craftsdwarves, but they will still do their jobs if workshop jobs are assigned, but it also means that non workshop jobs (like construct trap or link lever) will never be completed if your mechanic is on repeat build mechanisms, or if he's a mason/mechanic on a repeated masonry workshop task, like blocks or tables/chairs.
Basically, job priorities have gotten stricter. If a dwarf is doing the wrong thing, you may have to forbid all other activities to enforce compliance, but in general more dwarves will take the initiative to complete important tasks without oversight, and productivity goes up in most cases.