This was only true some time ago, unfortunately. The technique used by both companies to achieve speed increases is called 'pipelining', which essentially means

This was only true some time ago, unfortunately. The technique used by both companies to achieve speed increases is called 'pipelining', which essentially means you can have a different instruction in each bit of the processor (so, the ALU, the instruction fetch, the memory unit are all doing different instructions). The problem with this is that pipelining only works on instructions that have a very regular format, and run in a similar number of clock cycles, and the only way to keep instructions heterogeneous is to not have very many of them! Intel, however, supports a massive instruction set, with some hugely complex instruction. They do this by actually "compiling" their complex instructions on the chip to a format which looks a lot like ARM instructions, which they call micro-ops. I would say that the ARM architecture is inherently better, because it does not waste all this silicon to do instruction translating, and you know exactly what is being executed on the processor, simplifying the job of the hardware designer, and allowing them to focus solely on performance (/power consumption/whatever), and allowing compilers to do instruction level fine tuning.