I think the B&W 800 series speakers are great. I have a pair of the 805's, which are the bookshelf speakers. I've heard B&W speakers described as "revealing", which I guess is accurate. I have mine paired with an SVS subwoofer, so I'd describe my system as revealing... and a little warm. If that makes sense.
Be aware that there have been several versions of the 803 series speakers. There was the original 803 and an 803D (which uses a diamond material for the tweeter and probably other upgrades). There is a substantial price difference between these models. Mine are the original 805 series.
I've heard the 803s (originals) and really liked them. They have just a big more weight than the 804's and 805's. They can be very revealing of your upstream components too.
Like all speakers, I think what you like is very personal. An audition would be great, but maybe not feasible and honestly, as has been mentioned, an in-house trail would be best. B&W speakers tend to hold their value, so if you decide they aren't for you, you can probably get your money back.
And price always matters. Well, to most of us anyway.