You can see rhythms as a line where a bar is split up in e.g. 16th's. Now if you use 1/16 quantize, everything is bang on these divisions. Then, if you analyze for instance a shuffling rhythm, the down beat, snare or clap and a hi-hat programmed in 4's or 8's will be straight still, but every event that occurs on beat 1.1.2.1, 1.1.4.1, 1.2.2.1, 1.2.4.1 etc will be delayed a certain amount. This is where you would use the 16A-16F quantization options: 16A resembles 1/16 a lot, while with 16F it's not really straight at all anymore. It's beginning to sound like a walz or something. When it comes to dance music the trend is definitely swing, at least 16D (I've found out that US sequencers like Studio Vision and Digital Performer go between 16D and 16E (value 71 on the upbeats). It slows the track down a bit, but it makes it more funky and hip.