Used vs. new

It’s the same issue with automobiles, so when you can come to terms with that you can with this. 

I heard the big B&W speakers at Axpona with McIntosh gear and they sounded amazing! There is also a dealer 30 min away and they sound great there too. I think you will be happier with the larger version 802s. Good luck ! 

If buying used nothing too old under 10 years old unless fully rebuilt,

and check for condition minimum ,Excellent to Mint, and quality of brand counts 

they typically use better parts quality  ibought some very good Dynaudio  contour 

loudspeakers like new and totally rewired and rebuilt the Xovers ,it  is at least equal to any $10 speaker for a  $5k investment.

with digital I would not. For Digital has progressed many times in the last 5 years. 

"it’s a tricky situation since I have no way of listening to either one to see what I like better."

you can buy and keep them for 30 or 60 days and then return them with full refund.

once you narrow down what would match your space, amp, sources, preferences, budget, musical genre, you would be looking at about 5 brands and 10-15 models. You can stick with B&W to compare everything to, but you’d be happy to learn and appreciate what else you can get. There are high quality bookshelves that are better value than B&W, but again it all depends on everything else and the dirty S word - synergy

I bought L,C,R, Paradigm signature speakers from a vendor on the opposite side of the states. Each of the speakers had an issue with the tweeter and the center with one of the mid driver.  Before the purchase the seller sent pics of the speakers before I purchased them.  The seller paid for all new replacement drivers, tweeters.  So, buying used is challenging , but can have big rewards.