technically similar to the S510H the S810H:
- Mini USB for firmware update and contact synchronization
- 2.5mm headset jack
- Bluetooth
Neither of my SX1 base still N510 I can between the S810H and S510H (Pro) notice a difference what range or sound quality is concerned.
The advantages of S510H come especially when multi-cell system N720 to wear, because here I have even the "normal" S810H tested and had constantly crashes during handover (but not always) in the Pro series it works flawlessly.
For me at home the S810H in the Black Edition rich would (find black just nice) but unfortunately there is no longer this.
The only thing I find a bit strange:
I have an older telecom headset with 2.5 mm jack. AM E49H, S79H it works - but not at the S810H and S510H.