Hello all, I was a previous owner of the Yamaha 5990 and recently purchased the 6090 as a replacement for it. I wanted to highlight a few of the differences between the two in features so that you can make an informed product buying decision. In the next few weeks 5990’s will be going on clearance in order to make room for this new piece. Maybe you’ll decide to go higher up on the Yamaha product line to the RX-V series, or try a different company. You decide - Specifications - As it sounds right now, just listening with my ears there seems to be no audible difference, but there are a few specs that a different inside from the last model to this model. Dynamic Headroom 1.1 dB on the 6090. The 5990 had 1.03dB Dampening Factor (IHF) 150 or More on the 6090. The 5990 had 140 or more Maximum Input Signal on the PHONO is 60mV on the 6090. The 5990 has 100mV The total weight of the product from the 5990 to the 6090 has dropped by 1 pound. From 37 lbs. to 36 lbs. - Features - The 6090 does have a couple of impressive new features which were the main reason I decided to purchase it. Full pass through of 1080P video signals. The 5990 can only do 1080i. Yamaha’s proprietary iPod docking system. Using Yamaha's YDS-10SL iPod docking system you can connect your iPod to the receiver, control it, and charge it all at once. It works flawlessly and charges even when the unit is turned off (Although you can turn that off). - Losses - With all those new items older features have to go in order to make room and keep the pricing bracket. The 6090 looses THX Select 2 Certification. As I said, the system seems to sound on par with the 5990 so I think this may have simply been used to save money by forgoing the expensive process of getting the branding. But if you see some of the slight differences above in specifications these maybe where the receiver fails to pass (I’m technical but not THAT technical). The Front Speaker "B" Channel is gone. Advanced Install Controls are gone. This included RS-232 input for advanced remote control systems, and the 12V triggers used to trigger other electronics in the room to turn on or off (such as a drop down screen, or lighting controls). Those are the major differences between the two pieces as far I could tell with less then two hours with it in my audio rack. I hope this helps you out when attempting to decide what to purchase.