I don't think it's "the next big thing." Not everything needs to be. I'm making a synthesizer with the Arduino Due (and Teensy which is compatible). It's a fun playground for things I would never normally get to do in C++ and asm. I've never gotten to code on a platform with true realtime and no OS restrictions before. Also the barrier to entry is so low, it makes it so much fun. WIthin less than 15 minutes of receiving my Amazon package I had my my first blinking LED working.