I am so close to pulling the trigger on a new AV receiver and have pretty much determined it'll be a Yamaha. I have done my best googling but I cannot for the life of me determine exactly what the difference is between the 2070 and 3070 except for 1) Price and 2) Adding external amp for 10+ channels. Is there any other reason to get the 3070? It's such a huge bump in price (approx $500) that I just can't see needing to go that way except my gut keeps saying "get the best one!!!". Any advice would be greatly appreciated!