The best Raspberry Pi available right now is a bit faster than a modern entry-level PC. It has 4 ARM cores running at 1.5 GHz and 8 gigs of RAM.
It's certainly much better than the original Raspberry Pi (which felt like a 486), but it is not using recent technology and it just doesn't compare to what is available today. It is for projects where you would normally use a microcontroller, but want HDMI and Linux out of the box. People using the Pi for art projects, signage, dashboards, controlling their sprinkler system, etc. have the right idea. People using them to serve interactive traffic are going to have a bad time. They are really, really slow.