Being a Cal native I can't disagree with any of the above and those will be my votes as well, mostly for the same reasons you mentioned. If the "yes on 8" people really wanted my yes vote, they should extend the proposition to outlaw marriage altogether. Either everyone have an equal right to be miserable or else no one.
To my friends that don't bother to read up on the issues but go and vote anyway, I tell to vote NO when they can't understand it because its a vote for no-change / status quo. Silly, I know, but better than voting Yes on something they don't understand. TV ads and billboards for both the Yes and No sides always talk in purely misleading 'positives', intended to confuse and stun the masses that won't bother to do their own research before voting.
Oh, for Prop K, on the surface it sounds fine to decriminalize prostitution, but I can see the other side of the argument that people don't want home prices driven down by any increase in streetwalkers. If Prop K could somehow put cheap laptops in the hands of whores so they could hop on to city wide Wifi and post a craigslist ad rather than hang around in dark doorways, that might make some people happier.