I think it's completely hit-or-miss, depends on the day, the SA, the weather, what I'm wearing, what I'm feeling, how high I'm holding myself
I've been into H stores from NYC to Florence, and in some instances, the SAs have been overly helpful, even obnoxious (NYC Madison, Bal Harbor), to entirely removed and unresponsive (London Sloane Street, NYC Wall Street), and somewhere in between (Bordeaux, London Bond St.). And, I have never purchased anything at Hermes, so that can be a reference point as well...
I think that if you know what you're looking for or what you're looking at (names of leathers, colors, bags, etc.) that seems to help with warming the cold heart that can be an H SA, and also just ignoring their snottiness when it comes out
Overall, I would say not any different from other brands and stores. I get terrible service at Louis Vuitton stores sometimes, even when I have purchased things there before, and am wearing multiple visible LV items...(so random and bizarre if you ask me).