You can start from a LiveCD and check of everything works (Wireless, sound, etc).
As Ocicat mentioned, not all Acer Aspire models are alike, and there can be great differences even if the model no. is the same.
This way you can see which works better without reinstalling.
For OpenBSD, I recommend jggimi's LiveCD:
http://jggimi.homeip.net/
I don't know of a FreeBSD LiveCD that isn't either very old or that doesn't suck ... Maybe someone else can offer some suggestion there.