After using AI for a while as a developer, my feeling is

• It's really good in the initial scoping, design, and R&D phases. Initial implementations are pretty good as well -- how to lay out a set of functions or classes that form the scaffolding for your project. This is stuff that architects and developers could sink a month into. A single, good developer could use AI here and come out with an overall design that's probably as good or better in a couple hours.
  
• Very good at basic/intermediate coding. Saves a good amount of time here.
  
• It seems good at the QA/unit testing phase, but it lets a surprising amount of things through.
  
• It's good at basic debugging -- "this error message/exception at this line means you need to fix your code this way".
  
• On more complex debugging it gets into cycles and thrashes. I've had a number of instances where I've spent 2-8 hours and it only ends because of human intervention/observation. That's a "me problem" to some degree, but there's a very real skill to knowing when you have to step on it pretty hard to get it pointed in the right direction.