Ask HN: Which is the better macbook pro of these two?

So, I have been asked if I want to have a new mackbook pro at work as someone left and their laptop is going spare. When I go to system information, my current mackbook has: > MacBook Pro (Retina, 13-inch, Early 2015) > Processor: 2.7 GHz Intel Core i5 > Memory: 8 GB 1867 MHz DDR3 > ---------------------------------------- > Model Name: MacBook Pro > Model Identifier: MacBookPro12,1 > Processor Name: Intel Core i5 > Processor Speed: 2.7 GHz > Number of Processors: 1 > Total Number of Cores: 2 > L2 Cache (per Core): 256 KB > L3 Cache: 3 MB > Memory: 8 GB > Boot ROM Version: 180.0.0.0.0 > SMC Version (system): 2.28f7 and the newer one is: > MacBook Pro (13-inch, 2017, Two thunderbolt 3 ports) > Processor: 2.3 GHz Intel Core i5 > Memory: 8 GB 2133 MHz LPDDR3 > ---------------------------------------- > Model Name: MacBook Pro > Model Identifier: MacBookPro14,1 > Processor Name: Intel Core i5 > Processor Speed: 2.3 GHz > Number of Processors: 1 > Total Number of Cores: 2 > L2 Cache (per Core): 256 KB > L3 Cache: 4 MB > Memory: 8 GB > Boot ROM Version: 190.0.0.0.0 > SMC Version (system): 2.28f7 They seem so similar and yet the newer one has a lower Processor Speed. Interested in your thoughts.