Thanks to you all.
Your input has been very helpful in deciding on my new campaign.
Almost everybody seems to be in favour of S&P (I had expected mixed
feelings). There seem to be some common suggestions, so I'll try to
sum it up:
1. say "NO" if somebody wants to create a gamebreaking character
2. exploit the character's weaknesses
3. create villains with S&P/S&M
4. skip customization for demihuman races and priests

anything to add?

thanks again

Kai* remember: coffee keeps you awake, so don't drink too much at work