On this particular machine I'm using, some distros have excellent sound out of the box and some require snoop=0 added to the snd_hda_intel options in /etc/module.d/ to avoid stuttering audio. I didn't discover this bug until after I'd bought the motherboard and tried various distros; in my research it never came up.

And on a completely different note, I have a Dell Latitude laptop from around 2000 or so, a Pentium III machine, that has no built in networking unless you count the dial-up modem. I picked up a random CardBus wifi card for $5, and OpenBSD recognized and configured it flawlessly.

It really all comes down to whether the OS developers have access to the hardware the rest of us use. If, for example, your wifi doesn't work, it's not likely to until enough bug reports are submitted that the kernel hackers responsible for wifi drivers get their hands on the hardware and write or improve a driver. It's the same for those trackpad issues you had; someone somewhere has to debug that.

This is why it's a good idea to research your hardware if you intend to run anything other than Windows or OS X. And even with research, it's rarely 100% working out of the box. That's the tradeoff for having what (in my opinion) is a very productive and comfortable working environment.