[michelledepeil]

My suggestion would be a refurbished Thinkpad X230 and install a nice stable Linux distro (Linux Mint with XFCE for instance). It's open and repairable enough to scratch that itch, and the specific flavour of Linux gives stability but also configurability and exploration options. Get a low-spec laptop and start by replacing the HDD with an SSD and adding more RAM, then creating a bootable USB and installing the OS.

IMO the RPi is quite fragile , and the PBP seems a bit fragile and _very_ unstable to me, though they are both certainly far more open/free.