You can compare the 6300 to 6500 - 6600 on the Janome website. Well you can compare in writing anyway.
I have the MC6500P that I purchased online from America-Sewing. com and I LOVE IT! Got a Great price. I have used several of the stitches but will never really use them all that much. With my machine, I did received the extended table and numberous feet including the walking foot at no addtional charge. Just besure to ask what all is included with the machine you are considering. I actually bought mine sight unseen except online. I have had NO regrets at all! Good luck in your decision.