Okay - my experience with all three of these mediums of gaming are varied and I certainly don't have as much experience with some as others.
First off, the next person to tell me that Chat-based and Play-by-post are "slow" styles of gaming, I will tell you that you fail. You don't know the live games I've been in and just how slow things can get.
Live gaming does not mean a weekly game. It doesn't even mean a monthly game for me. It is a "we'll try to get a game in each month, but if we miss a month or two or three, no biggie." This is why my monthly game ran for 2 years, had 4 sessions and the characters didn't level up over the duration. At the end, I decided to run that same adventure in a play-by-post format and in less than two years, they are just about ready to level up and have eclipsed