go for onkyo and you will never regret it. Only try to go one step higher since 507 does pass through only on the hdmi.... go for 607 or even the 606 will be fine.
I had my Tx-sr876 with jamo C series for almost a year now and its superb for both movies and music.
The onkyo 507 has HDMI 1.3a repeater and not pass through.
On top of my head, Onkyo 507 over Denon 1610:
- 80watts/ch vs denon 75watts/ch
- 4 HDMI ports vs 3
- HDMI port is already CEC
- Learning remote
Denon 1610 over onkyo 507:
- Audyssey MultiEQ vs Onkyo Audyssey 2EQ
- Dolby pro logic IIz - although you need a seperate amp for this
- Analog input