Now I used FreeBSD 8.0-Release (updated to 8.0-RELEASE-p2) and it seems to be much better than last time, especially in the USB front. I also like the freebsd-update capability. It seems to be faster than last time.
What I like compare to Linux: maybe the BSD license itself. But now I feel GPL/LGPL are not bad either.
What is not working: my SATA DVD-RW is not recognized at all. This is an Acer M1641 desktop with NVidia 620i/Geforce 7050 based chipset and FreeBSD seems to have big problems with NForce 620i and 630i.
What I do not like: the port system. I have since removed most of the packages initially installed (LXDE, KDE3, KDE 4, QT33, QT4, etc) due to the mass upgrade of libjpeg. It caused big problems to many packages. So now I have a bare-minimum Gnome 2.26 based desktop (dare not update to 2.28). Mass upgrade takes a long time and often the ports are broken. ARCH seems to do a much better job since binary updates are provided. I still like Ubuntu's package system (deb/apt, Synaptic) the best.
My libusb testing on FreeBSD: pk2cmd seems to behave like last time, but now I do not need to recompile the kernel. libusb based programs work better but there are still problems.
My OpenOCD test on FreeBSD: FT2232D seems to work, J-Link V3 does not work. J-Link V7 seems to work. All of them works under Linux.
My main interests with FreeBSD will be more libusb/MCU related -- to get OpenOCD (J-Link and FTDI, for ARM MCU development) and PICkit 2 (and other PIC related things, for PIC development) to work well under FreeBSD. Now it seems that FreeBSD is an possible platform for MCU development.