Have never used mine. I prefer the beaglebone.
Raspberry pi and it's Broadcom
chip are a bit too closed source for me. And it has nearly no expansion pins.
Yes, that was a major problem for me too. OK, it is clearly impossible ot
pring any kind of real processor bus out,
On the beaglebone you have access to the
GMC bus. That is a system memory interface... And I have experience with other systems
that bring out reasonable CPU busses!
Philipp