For some time OpenBSD has been regarded as "slow", in big part because it couldn't use large amounts of RAM, and it scaled across multiple cores poorly. I'm not sure if this is still the case.
Hmm, really? I love OpenBSD, but last I checked the installer tells you to create slices then drops you straight into fdisk. Has this been polished up? I'm just concerned "one of the easiest to install" would give a n00b the wrong impression.
The partitioner on Ubuntu's LiveCD is easy to use. (Choose full disk and go)
Several potential security problems have been identified and fixed."