I thought the common belief was if you're playing a team more talented than you, you want to play a slow pace. If you're playing a team less talented you would want to speed it up.
I'd tend to agree with this most. If you know your defense is likely to struggle to stop your opponent, you want to minimize the number of possessions so that you need less luck to end up getting a win.
More generally, against a much better defense, it depends on your flow and shooting skills. If you have crappy flow and decent shooting, you might as well jack up the first shot you can since you're unlikely to hit and unlikely to work it around to get enough of a 'better' shot to make it worth the increased risk of turnovers. With decent flow and crappy shooting, you might want to slow it down to try to get more 'open' shots.
I just know that I always loved to see teams try to run fast offenses against my team when it was a good defensive team back in the day - they'd end up getting a lot of bad shots and then my efficiency in avoiding turnovers and balanced flow ensured that I'd usually score just enough to win games.