How do the BSDs compare to Linux for apps, performance, stability, updating, etc.?
They are both moving targets since they are both in active development so this isn’t completely clear cut. Both run a lot of the same hardware and a lot of the same software is available for both. BSD has historically been better at handling large volumes of traffic while the same box with Linux becomes unresponsive and sometimes crashes under extreme loads (2.6 has really improved Linux). The BSD’s have been easier to keep updated and upgrade between releases than Linux. Linux has had better SMP support than the BSD’s but FreeBSD is making good headway into closing that gap. NetBSD supports smp on some platforms and OpenBSD supports uniprocessor at this time.