The new models have updated 14 nm Intel Core m3, m5 or m7 CPUs, with up to 25% fast graphics, faster PCIe storage, and longer battery life. Unfortunately, still no Thunderbolt 3 or 10 Gbps USB-C — these should arrive next year.
The new MacBooks appear to be about 15% faster overall in the synthetic Geekbench benchmark over last year’s model.
P.S. The 13″ MacBook Air now has 8 GB of RAM standard, instead of four.