Hmmm. Right now I'm playing with the Parallella the most, because it arrived last week. Before that it was the Pipistrello, and I assume that when the Logi-Pi arrives, it will get the majority of my attention. I like them all differently. The Papilio was my gateway drug. I had the Papilio One and the Pro first. Getting the Pro got me interested in the Spartan 6, and that led me to the XuLa2, with a Spartan 6 LX 25, and a breadboard form factor, and that had my attention for a good long time, but the relatively lack of GPIO kept me going back to the Pro. Then I had the opportunity to pick up a Pipistrello, and its Spartan 6 LX 45, with roughly the same peripherals as the XuLa2 (SDRAM, micro-SD card slot), but with as much or more GPIO as the Pro, distracted me for a good long time. I've become a believer in the CPU+FPGA fabric combination, which attracts me to the Parallella and its Zynq chip, the Logi-Pi with its integration with the Raspberry Pi, and now the Duo and its Atmel chip on board. Basically, I love them all, the one that gets my attention is usually the newest. Hopefully I will eventually have a project worthy of publicizing.