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.

My laptop has an Intel card, and everything is nominally supported.

You are free to be surprised all you wish: I went back to linux because I was sick of dealing with the system locking up for 5-10 seconds every time I opened, closed, or switched to a new browser tab. Couple that with 1-2 fewer hours' worth of battery life and I found myself very quickly asking what the point of "code correctness" was if the system just doesn't work.

A thoroughly frustrating experience from top to bottom.

Just saying. If you haven't already, I'd definitely send them a bug report and dmesg; that all seems very abnormal.

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?

Well, it's not called "stable".