The Yamaha is the better buy. The new AVR-**13 receivers are very disappointing as are the models below the AVR-23** because of loss of digital audio inputs and analog A/V inputs and lack of any recording loop. The Yamaha are great and offer a lot. I had a Yamaha RX-A710 but had to send it back because of HDMI problems and HDCP problems. Design defect or just defective, don't know, but I wanted I/P scaling for HD sources since I was going to get either a RX-A810 or AVR-2312ci and also wanted Room correction for the subwoofer. Since the RX-A810 had none of that, I went with the Denon AVR-2312ci.
I do prefer the sound of Denon over Yamaha. I had a Yamaha RX-V793, RX-V995, RX-V2095, and a RX-V2300 and none sounded as good as my Denon AVR-3803 while being pushed or in the airy treble at moderate listening levels. Yamaha never sounded bright but it didn't seem to be as musical or have the musical definition that the AVR-3803 ($1200 MSRP). I compared the best Yamahas to the Denon, the RX-V2095 ($1,700 MSRP) and the RX-V2300 ($1000 MSRP).
I never did setup the RX-A710 to poperly listen to it since it had HDMI problems and HDCP problems.
The Denon AVR-2312ci sounds just as good if not better than the AVR-3803 even if it doesn't push as much current as that beast.
However the Yamaha RX-V673 has everything for a great price. It has both A/V recording loops and Audio Recording loops (which even the highest Denons AVR-2312ci, AVR-3312ci, AVR-4311ci, AVR-2313ci, and AVR-3313ci do not have an audio only recording loop). The Yamaha doesn't group connections together for an input but make each connection it's own input. So you have more inputs to add more gear with the Yamaha receivers. BUT if you need a digital audio and analog video combination that isn't offered, you may have to use 2 inputs (which is allows for) to make a compatible input for a device. Yamaha's offer more connectivity than any other receiver.
The Denon AVR-1913 deleted the Dock input and deleted the AM tuner (local news, weather, and sports!). It also offers absolutely no audio or A/V recording loop at all and only offers 1 toslink and 1 coaxial digital audio input. Very very limited on connectivity. To go with Denon again, I could go no lower than an AVR-2312ci just for system compatibility.
If I didn't buy the AVR-2312ci, it would definitely be the RX-V673 or the new upgraded RX-A720. BTW, Yamaha has always tested pretty low on power output by S&V and Home Theater magazines but then again they don't test true 20hz - 20Khz power output or dynamic power output which actually matters instead of 1Khz power and steady state RMS power. Just so you should know though. It was disappointing with how bad the RX-V871
tested out at Home Theater Mag. compared to the Denon AVR-2311ci
that have good power output. The Yamahas also have subpar video performance as well but maybe the new models perform better.