The B&W 803S have the better real wood veenered cabinet. They are aesthetically beautiful.
The Jamo C809 simply sound better, if you're not into edgie, bright harshness.
If you're into edgie, bright and harsh sounding speakers; the B & W 803S is the speaker for you. Some people will like it, other's will not.
Or if your main concern is the aesthetic beauty of the cabinet.
As for tone controls, I use them when ever necessary for jacked-up recordings/masterings. Now with my McIntosh C220 and previously with my Vincent Audio SA-T1 preamp.
Tone controls don't solve the B&W 803S's problems in their brightness/harshness. I know, I attempted to do that when I auditioned them. It's inherent in their designed sound. You have to reduce the treble so much that it does major damage to the overall balance of the sound.
The Jamo C809 only require a slight tweak of the Treble and/or Bass to reduce the jacked-up treble of some recordings/masterings.
The Jamo C809 are much smoother, much more inoffensive, much more musically pleasing and appealing than the B&W 803S; in my opinion....of course.