Older laptops are definitely the way to go with OpenBSD. I have a Thinkpad T430 that used to run OpenBSD. The one thing I had to do was disable the Nvidia card on there and set the IGPU as the primary, which was done in the BIOS. After that it worked great on that hardware and OpenBSD can be a solid desktop OS. Servers are a different matter: I almost exclusively use OpenBSD. httpd and pf out of the box is a huge selling point.

Now that being said, I eventually found that OpenBSD didn't offer everything I needed for a daily driver, so I moved to CRUX Linux. It's the closest you can get to BSD while still having Linux-only features like NVIDIA support. Writing your own ports is waaaay easier than on OpenBSD, too.