A friend of mine and I were discussing the use of Plasma Pistols on Chaos Space Marine Champions. He swore by them, and he really liked them in combination with the potential Preferred Enemy: Space Marines.
I, however, vehemently disagreed. Here are the specifics as to why I dislike them.
1. Point cost. If a number Plasma Gun runs from about 10 to 15 points, why should a Plasma Pistol be 15? Some would argue that the benefit of a Plasma shot on the charge and the extra close combat attack is the benefit. But for less points, you can get the same value for longer range and more shots? I don't think PPs are really worth it. Particularly because..
2. Risk. If your Champion/Sergeant rolls a 1 and fails that armor save, you have lost WAY more than 15 points worth of effectiveness. Generally, you lose 1 LD, 1 A AND whatever other upgrades he had. Not worth the risk to fry yourself.
This is, of course, my personal philosophy when choosing wargear. I'm interested what others may have to say about it?