B&W Nautilus 803 or B&W 702 S2?

If you want musical sounding speakers I would look for something else other than B&W. Something from DeVore Fidelity, Sonus Faber (at least Olympica line or higher), Harbeth, Roger, Spendor, ATC, ProAc, Accoustical Engineering, Vienna Acoustics, Wilson Audio, Wilson Benesch, Magico, Raidho, Vandersteen.

B&W 800 series D3 is great for home theater and is one of my favorite high end home theater speaker system but not for 2ch music. If it's for 2ch music your money isn't wisely spent on B&W.
There are countless other cheaper options than B&W that are better for music. 

The B&W 800 series D3 aren’t bad for music but my point was that there are other speakers that cost less than the B&W that are more engaging with music and are more musical overall with richer timber and tonal color and possess more natural organic relaxed presentation and fuller sound than the B&W. When used for music to me B&W musical presentations sounded somewhat processed lacking natural organic sound especially with vocals and string acoustic instruments lacking midrange bloom and image depths and possess very forward presentation that I found them can be somewhat unpleasant at times for music especially with standard resolution digital recordings such as that of bad CD recordings. To me B&W fails to convey that lush emotional expressions of the artists and players.
I think I am not the only one who feels that way.

However, when it comes to details, clarity & resolutions B&W is top notch but that isn’t the only crucial elements that I’ll be looking for in order to achieve musical enjoyment from a system. Details, resolution, attacks, speed are important for movies (home theater), especially with those lossless HD surround sound formats eg DTS HD MA, Dolby True-HD, Dolby Atmos, DTS-X, which makes movie watching experience very exciting. That’s what B&W 800 series D3 are good at IMO.

I have to admit that the 800 D3 models are quite a bit better than their predecessors D2, D1, etc etc. I just couldn’t stand the previous B&W 800 series D2 models. The D3 are indeed better more realistic sounding than their previous D2/D1 models. B&W finally realized and moved away from using kevlar material for their midrange drivers.

But again it all comes down to personal preferences and tastes when it comes to speaker choices. You and others don’t have to agree with me.

B&W is perfect for home theater application IMO and is my to go choice for home theater.
I’m not bashing B&W as I am a B&W owner myself strictly used for my home theater room. I do own the latest B&W 800 D3 speakers for front with the matching HTML1 D3 center speaker and all custom theater in-wall B&W 800 series D3. I love them. They are spectacular.

Like I have already mentioned above that yes the D3 is more refined and have different sound profile than the D2 and indeed more musical than the D2 but they are still other speakers that cost less than the D3 but more engaging with music.

As far as synergy.....well, my B&W 800 D3 are in my dedicated home theater room strictly for home theater duties.
I drive them with the Classe Delta CAM-600 monoblock amps (class AB) and they sounded terrific together. I am using Transparent Reference speaker cables for them.

However, I have also tried driving them with my other amps that I have had in my separate dedicated reference 2ch room. So we literally dragged my B&W 800 D3 over to my dedicated 2ch listening room and had them hooked up with a pair of D’Agostino Momentum M400 monoblock amps before with the ARC Ref 10 linestage preamp + DCS Vivaldi full four stacks served as my digital front end as well as the Kronos Pro turntable + ARC Ref 10 phonostage pre served as my analog front end. I had some people help me with the move and placements and everything as the 800 D3 are big and quite heavy.
And when I compared them to my previous Wilson Audio Alexx that I had in there at the time, no comparison.
My speaker cables are Transparent Magnum Opys. Interconnects and power cables are Transparent Opus.

Recently I went through a significant upgrades with my stereo setup that I have in my dedicated refetence 2ch listening room. I traded in the ARC Ref 10 linestage pre and the D’Agostino Momentum M400 monoblock amps for the Naim Statement gears which consist of the Naim NAC S1 linestage preamp and the Naim NAP S1 monoblock amps. I also traded in my Wilson Alexx for the Magico M6. But I keep my DCS Vivaldi full four stacks as my digital front end components and I still have the same Kronos Pro turntable with the ARC Ref 10 phonostage pre.
Last week we had my B&W 800 D3 dragged over to my reference stereo listening room again and had them hooked up to my new Naim Statement gears and compared them to my Magico M6. No comparison. I know it isn’t a fair comparison as the Magico M6 cost $176k a pair and the 800 D3 cost only $30k a pair.

IMO the Sonus Faber Olympica iii ($13,500/pair) and the Olympica ii ($10k/pair) are more musical or I should say more engaging with music than the B&W 803 D3 which retail for $17k/pair. My friend happens to be a dealer for both B&W & Sonus Faber and one time we had shootout between the SB Olympica iii and the B&W 803 D3 at his shop. Both speakers were paired with Classe Delta CAM-300 monoblock amps (class AB), Audio Research Reference 5 linestage preamp and a Naim ND 555 streamer/DAC + Naim 555 PS DR separate power supply unit.
So all the electronics are of high bars and we sat down for at least 2 hrs listening and comparing between the two speakers. We found that the SB Olympica iii is more engaging with music especially with piano and string instruments. But when we fed them with high resolution materials of great recordings we found the 803 D3 to be quite engaging and it’s got to the point where I can easily live with them with high resolution materials of good recordings.

@auxinput

True. I have heard the B&W 802 D3 at the shop driven by all McIntosh tube power amp and preamp and didn’t like the sound at all. For some reason, B&W will not pair well with some tube amps, not all. Better off with SS amps. I think the B&W D3 do pair well with SS McIntosh amps, Classe Delta series class AB & Classe Omega series class A amps, some Sim, D’Agostino, Ayre & Naim amps among others.

My B&W 800 D3 front speakers that I have in my dedicated home theater room are driven by a pair of Classe Delta CAM-600 monoblock amps (class AB) and they sounded spectacular together. My matching B&W HTML1 D3 center speaker is being driven by a single Classe Delta CAM-300 monoblock amp (class AB), and the rest of my surround speakers (matching B&W 800 D3 series custom theater in-wall speakers) are driven by two Classe Delta CA-2300 stereo amps (class AB). And finally, my 4 overhead height ceiling speakers for Atmos setup are driven by two Classe Sigma Amp2 amps (class D) since my new Lyngdorf MP-50 AV processor does not have RCA single-ended analog audio outputs only XLR. For those 4 overhead height ceiling Atmos speakers I was originally gonna get the Clase Sigma Amp5 five-channel amp but the problem was that the Sigma Amp5 has XLR inputs only for first two channels and the rest of the channels are only available in single-ended inputs. Overall, they all sound terrific together for home theater use.

However, last year I did try bringing my B&W 800 D3 along with the Classe Delta CAM-600 monoblock amps over to my dedicated two-channel listening room and hook them up with the ARC Reference 10 linestage tube preamp that I had at the time with the DCS Vivaldi full four stacks (Vivaldi master clock, Vivaldi upsampler, Vivaldi DAC, Vivaldi CD/SACD transport) served as my digital front end source components. They sounded spectacular together and those were great combo for the B&W 800 D3 IMO driven by SS amps (Classe CAM-600 monoblocks class AB) paired with the ARC Ref 10 tube linestage preamp. Then I also swapped the Classe CAM-600 monoblock amps with the D’Agostino Momentum M400 monoblock amps that I had in there at the time and the overall results was also spectacular.