>>1
are you looking for general information on their diff., or are you trying to pick one for an application? Their sites are pretty documented on their differences, so you do not need us for the general stuff. But I am interested, please provide more info.
Ignore
>>4, he does not know what he is talking about:
$ uname -ms && uptime
FreeBSD amd64
3:24AM up 5 days, 12:03, 3 users, load averages: 0.02, 0.04, 0.00