Originally Posted by Fat obi
I like to lead with Gengar because so many people lead with sleep. Gengar is the best sleep absorber (because it's still useful since it can switch into Explosion), and is strong enough to take on most other leads. I agree with Vineon that you don't want to risk losing your sleeper (my main team has Sleep Powder Exeggutor, and I bring it out once I know what they're going to try and absorb sleep with so I sleep what I want).
this, word for word, is exactly how I feel. The reason to use Gengar as a lead is because he's such an awesome sleep bait. Takes explosions like a champ and can even try to wake up again against a persian or surfing snorlax. The fact that gengar can use hypnosis himself is just icing.