As said, I've been playing with Nexenta (OpenSolaris + GNU + APT) a bit lately. Installed just fine in a Parallels VM, but in VirtualBox, the network won't work for some reason (tried with the latest SVN checkout, all different network adapters).
As I (currently) mainly want it for safely backing up my photos to two mirrored ZFS disks, I decided to install it using real hardware on two USB disks. After trying that, I got hit by the bad PBR sig bug.
Some googling revealed that this is somehow GRUB-related and can be solved by installing GRUB again. After some twiddling, here is how it worked out for me:
# after the installer completes, switch to screen 2 (Ctrl-a-n) cd /.livecd/boot/grub installgrub -m stage1 stage2 /dev/rdsk/c2t0d0s0
As usual, your mileage (and your device file for the right disk — have a look at the installer output for that) may vary. For me, it worked just fine and tomorrow, rsync (which was already installed using apt-get install rsync — that's how I like my Solaris) will do its share to move the photos to two USB disks ...