i've not tried the 'expensive' BW, but the 'phosphor bronze' alto that I bought for my girlfriend as a 'beginner sax' plays very well, for the money. the build is very robust, intonation is fine, etc. as with any other sax, a lot of variation in tone can be done by switching mouthpieces.
I did actually speak with Martin (of WW&B) about comparing the PB and the 'pro' (tenor sax) models when buying the alto (just out of curiosity), and his opinion was that the old PB horns are tougher & so should withstand minor knocks more easily. The 'finishing' on the pro horns is supposedly superior, but I've not have any functional issues with the PB horn either.
in a side-by-side with a YAS62, the BW sounded less bright, and perhaps a bit less refined. but certainly it's a sax i'd've been happy with, when starting out.
perhaps it would also help if you told us what you're currently playing & whether you're looking at an Alto or Tenor. If it's a Tenor, I think WW&B may still have a few of the 'old chinese pads' horns left, which are priced around 350 and at that price, quite a bargain. the pads are indeed rather sticky to begin with, but that problem goes away quickly.
finally, if you've not already spoken to Martin at WW&B, give him a call - he's a great guy to talk to & very helpful and honest about his products. (in my case, he gave me some advice on choosing a soprano & actually advised me against the more expensive of two horns i was considering, since he said it wouldn't suit my needs as well as the cheaper one... )
Hope this helps 😉