Really? I run it on a PowerBook G4, and while it's sluggish, it's not entirely "unsuable". If a 10-year-old single-core machine can handle OpenBSD, I'd be amazed by even the slightest performance issue on a quad-core, hyperthreaded, modern PC. What's additionally surprising is that this is the case on a Thinkpad, of all things; IIRC, the OpenBSD devs dogfood OpenBSD pretty heavily on Thinkpads due to their FOSS-friendliness.

Does your laptop have an Nvidia GPU, by chance? In my experience, those do tend to have very bad performance on OpenBSD. Intel and AMD/ATI GPUs should work better.

Also, it's worth mentioning that OpenBSD's kernel has a whole slew of debugging and error checking features compiled in by default; compiling a custom kernel without such features can be done, but the docs don't really recommend it, since it becomes excruciatingly difficult to troubleshoot any problems with it.

One risk of using OpenBSD is a lot, but not quite enough, people use it on enough on random hardware and give actionable feedback to make it battle-tested, "Just Work" (TM).

"The test series, unfit in our view for production use, will however continue to be available to the public to avoid impact to the Gentoo Hardened and Arch Linux communities."

Why would you have to migrate to OpenBSD? Is the test series unstable?