Boutiques:
Omega boutique - lots of stock from the latest releases, and amazing staff - the store manager who was a watch enthusiast and ended up talking about about her partner's new Christopher Ward - which is a nice demonstration for empathetic selling, I guess.The staff member who was helping me didn't know as much about watches in general, but knew enough about their own stock to bring me out a watch I hadn't considered and ended up going back and buying a week later, so very much credit to him as well. Overall a very positive experience.
Lange boutique - I believe this one is a joint venture with a previous AD: staff were friendly, but stock was limited. Salesperson didn't give the spiel about Lange's finishing technique à la Tim Mosso - either he didn't know or he figured I knew already. Overall a positive, if generic experience - definitely felt catered for, but not particularly Lange-y. Did end up buying there as the customer service was good and I knew enough about the product without the salesperson telling me :P
Chopard boutique - very motivated salesperson, spent a lot of time bringing in all the latest models for us to try. Almost bought an Alpine Eagle, but the movement finishing was too industrial (if it was the xps series I would have bought one!). Salesperson again was more generic luxury goods salesperson, rather than explaining how the AE is great as the case and bracelet is hand finished (had to look up that one later). She did know what a Geneva Seal was though, and how nice the LUCs were finished, so it makes me think that perhaps they were told not to get too technical with all the interior angle talk, rather than just not knowing? Overall another good experience.
Multi-brand stores:
The Hour Glass - they had some new Rolex sports models in stock (not sure if they're waiting pickup or actual buyable stock - if they were buyable then that was the weakest effort I've seen any salesperson give to sell a watch), and when we were done looking at those salesperson wanted to lead us to GP. Nothing against GP, but obviously the comment regarding neutrality for multi-brand stores is untrue - they'll just be biased for whatever they have in stock (i.e. not their patek, Rolex, or Journe). Wasn't allowed to try on any patek, salesperson wouldn't even bother leading us to Journe (even though I expressed interest). We did have purchase history - we still get the patek magazines from them - but they didn't ask and I didn't tell. Overall a poor experience, wouldn't be coming back again.
Local old school jeweler, multi-brand store - the standard polite refusal to try on patek, but the salesperson really came alive when I asked more technical questions about a pre-owned 5905 they had. Showed me the calendar setting functions in great detail off the cuff when I asked. Seemed like he really knew his product. Overall an excellent experience, seems to be the "local jeweler with good customer relations" that Thierry mentioned. Unfortunately forgot to ask for the salesperson's card, would have liked to order a bb54 with them.
In summary: depends on the store I guess. The most technically proficient salesperson was probably the one at the local jeweler, which is somewhat surprising given the boutique salespeople have fewer products to manage. It really gave an impression of selling a specialty product, which in my opinion is the sort of feeling a boutique would want to foster, over a generic luxury purchasing experience - after all, the point of going to a boutique is to make the brand stand out no?