I moved from a 2013 Air (maxed CPU and memory, but that was only 8GB, small SSD) to this same model, and I feel the CPU is about the same, or maybe a bit less powerful, even. To be fair, though, my bottleneck was usually memory (running several containers at full swing is not particularly CPU intensive but can easily eat 8GB of memory). So, for my day-to-day work, it is excellent, and to be fair, feels snappier and about as fast as the 2016 Pros the rest of my team has (I’m a consultant so bring my own hardware).
Of course, if your work is CPU bound a Pro makes more sense, but I’m only CPU bound when compiling or load-testing. For the first, that’s par for the course, and shaving 30 seconds out of a 4 minute process (say, compiling the Apache Spark codebase, in full from cold) is in practice negligible, since you are going to be waiting for a long enough while as to be a significant enough break as to require you to do something else. Same for running tests (although that’s usually the task of our CI provider). If you are constantly CPU bound, though (doing this many times an hour, like applying very large image transformations, or video encoding/recoding) the savings add up.
I’ve found a lot of people though (even my coworkers, who can see in real time how their Pros are not particularly faster or snappier for our day-to-day work) that consider that the Air is underpowered for development, and although I concede that it could be for some situations (I have heard XCode can be a CPU hog, but have little experience with it), my opinion is that it is an underrated machine that delivers enough punch to get the job done and keep your back in better shape.