I just installed FreeBSD 9.0 on an old Thinkpad G41 (searching for a system with an Xorg that supports the old nVidia driver, needed by this machine, and also hoping that FreeBSD 9.0 would prove to be a good release). Multiple times, due to installation problems.
The first problems I ran into were a result of using manual partitioning. I created a GPT partition table, but wanted separate [FILE]/tmp[/FILE], [FILE]/[/FILE], and [FILE]/usr/home[/FILE] partitions. In my first attempts, [FILE]/[/FILE] was not the first [FILE]freebsd-ufs[/FILE] partition and the system would not boot. Nowhere in the documentation, that I could find, does it say explicitly that [FILE]/[/FILE] must be the first UFS partition, but I believe it does. Yes, example 3-3 in the Handbook chapter on [FILE]bsdinstall[/FILE] shows you a sample multi-filesystem layout and [FILE]/[/FILE] is first. But this is presented as an example of such a layout and the constraints on that layout are not given explicitly. I actually looked at the [FILE]gptboot.c[/FILE] code to find the truth, and it tries to find a UFS partition with the [FILE]BOOTME[/FILE] flag set, which the installer doesn't let you set (unless you escape to a shell and use [FILE]gpart[/FILE] to create the partitions). Failing that, it uses the first UFS partition it finds. This really needs to be clearly documented in the Handbook and, at present, it is not (unless I've somehow overlooked it).
Another issue is that the Handbook states that the [FILE]freebsd-boot[/FILE] partition must be the first partition on the disk. This is simply not true. I looked at the [FILE]pmbr[/FILE] assembly code and it searches the partition table for a [FILE]freebsd-boot[/FILE] partition. Furthermore, as an experiment, I did a test installation on the G41 with the boot partition not first and the system boots just fine.
I then ran into trouble trying to set up wireless networking. I have multiple machines behind a NAT router and I want static IP addresses that I can stick in [FILE]/etc/hosts[/FILE] so, for example, I can SSH from one to the other, [FILE]rsync[/FILE] my home directory, etc. The installer found my base station just fine, accepted the WPA pass key and then asked if I wanted to do IPV4 setup. Yes. DHCP or static? Static, please. I then entered the IP address, netmask, and gateway address and clicked 'ok'. I immediately ended up back at the page that gives you a choice of network interfaces to configure. It did not proceed, as the Handbook suggests and as one would expect, to collect addresses of DNS servers and ask if I wanted to do IPV6 configuration. I have done this multiple times to no avail. The information I entered was correct. And if it was not, I would expect an error message, which I did not get. If I just click 'cancel' when it mysteriously loops back, I can proceed with the rest of the install, but none of the static IP setup info makes it into [FILE]/etc/rc.conf[/FILE] or anywhere else.
My wireless base station does allow you to configure its DHCP server to assign IP addresses based on MAC address, so the address assigned to a particular machine is predictable. I prefer using static IP addresses because it avoids the handshake time with the DHCP server every time you boot. But in this case, I was unable to get static IP address assignment working, so I resorted to DHCP, which did work.
I have a multi-year unhappy history with FreeBSD. I've tried it multiple times and always had to abandon it due to a show-stopping bug. I like the integrated BSD concept (as opposed to the wild and woolly Linux world where key components come from multiple groups who don't talk to each other) and I'm familiar with all the BSDs, including Dragonfly. Because FreeBSD is the largest of the projects and most popular, I keep hoping against hope that my past problems will not be a predictor of future performance. While this particular experience hasn't ended with a show-stopper -- I've found workarounds for the problems -- I had to invest an inordinate amount of time to get the system up and configured as I wanted it. This is not a good incentive for me to invest more effort in using this system. I contrast this with installs I've done of Slackware and Arch Linux, where things just go like clockwork. OpenBSD is similarly easy and trouble-free, until you get to wireless setup, where they have their own documentation problems. And if you ask them a question, chances are extremely good you will get shat upon, so I'm not about to bother. I'm not sure yet how I will proceed, but this initial experience with FreeBSD 9.0 on this machine has hardly been encouraging.