I'm responding from my 1.4, 16gb ram, 512gb ssd. My previous machine was a maxed out late 2013 MacBook Pro 15 (core i7, 16gb ram, 512gb ssd, Nvidia 750m), which is still going strong. This little 13" is a real beast. Comparing it to a hex core or whatever I suppose technically it's slower, but for 99% of people and the way they're probably using these systems, it's going to be ridiculously powerful and fast.
Howard2k is right as well about the entry level ssd being slower as well. If you opt for a 256 or 512 ssd though, it's faster, not quite same as 2.4 but much closer. if you look at performance benchmarks or use videos on YouTube you'll see the 1.4 and 2.4 are almost identical in performance for most tasks and benchmarks.