No question about it, RPi is more powerful in every way shape and form. That doesn't mean the arduino isn't better for certain things, though.

[quote]Arduino is fun to use, but I think RP 3 is more powerful.[/quote]Definitely. Arduino looks like the superior platform for projects that need lower power consumption. I'm looking at building a solar-powered weather station, with rain/wind/humidity/etc sensors, and the RPi looks like it will use too much power to run off of a solar-powered system. Spec wise, the Pis are much better, though.