What are the pros and cons between these 3 AV Receivers?

Of the three you want to get I would consider the Pionner VSX 1020 the best, it has the strongest amps and will be the most musical sounding with the widest variety of speakers, a lot has to do with what speakers you use how large a room and how loud you listen what type of music; but just generally speaking the Pioneer... the Yamaha would be next it is is a little less powerful than the Pionner but may be fine for you in a smaller room at moderate liostening levels depending on what speakers and especially good for movie sound, it may be a better buy depending on what type of discount, but because the Pioneer is an older model and has been replaced by the VSX 1021 the pioneer is probably going to have the deeper discount........The Sony is gooing to be big in features at a bargain price; but limited in the type of speakers it will handle well, because of a less powerful amp that is limited in output