Spend some time on the FreeBSD forum and you'll find lots of people using it on laptop computers. There's a list of compatible hardware to base buying decisions and there's a range of fully supported ones. FreeBSD itself is used most often for servers in terms of public consumption, but it's designed to be flexible in application, it's even in their mission statement. Another thing that makes FreeBSD more viable is it has a solid Linux emulator so anything you run on Linux you can also run on FreeBSD. Don't see any downside there other than hardware support. Linux does a better job of that, but the engineering and organization behind FreeBSD is a much better.