To be honest I find that OpenBSD and the BSD's in general to be a bit more intuitive than most Linux distros, that would be my main reason, OpenBSD specifically being the most intuitive, it's little things like connecting to wifi, on OpenBSD it's really straight foward from the command line but on Linux I just get a headache and I install a GUI for it, but maybe im just dumb and dont understand wpa_supplicant lol. OpenBSD specifically is a minimal OS but it's really usable out of the box, it feels complete unlike a lot of Linux distros, hardware compatibility is not going to be up to the Linux standard but I have never really had a problem on any ThinkPads. People say the performance for OpenBSD is not great and I suppose that's true as it's mainly focused on security but you can make tweaks to make it faster, I have mine in a startup script, but these tweaks will make it less secure. Also the structure of pretty much all the BSD's filesystems are cleaner than Linux's, everything has it's own place rather than being dumped wherever like in Linux, just compare the /bin on Linux to a BSD, it seems removed at first but then you get use to it and finding stuff is a lot easier, I actually understand my system now. Last, the codebase is smaller, for OpenBSD atleast, compare the GNU core utils to any of the BSD core utils and there is a difference of thousands of lines of code, but that's not really a Linux issue just a GNU issue.
TLDR: Feels like a complete OS, minimal, cleaner, more intutive than (most) Linux distros
Thank you, and yeah my wifi worked out of the box, ThinkPads really do just work under OpenBSD, I reccomend installing it other ethernet if you can however just to be safe that any drivers install correctly.