I find that I tend to have pleasant experiences at BB. Maybe the reason is that before BB came to Canada, Future Shop fill that role of big electronic store. I hated Future Show because sometimes, the salespeople just want the commission, but know jack about what I want to buy. If I know what I want to buy, I want to just grab it and go to the check out. If I need help, I'd ask.
BB on the other hand leave you alone to look around and I like that. Staff are very helpful when I ask for help. I never felt pressure to buy anything. One time, a rep spent 20 minutes helping me find something, but I ended up not buying anything because I could not find what I was looking for (a holster for a smartphone that is the right size for a Desire Z and a BlackBerry).
As for demo models, I find that not just Best Buy, but all other brick and mortar stores should follow Apple's lead and have working demos available for people to play with. Most stores have just sticker displays on most phones. Some have a working demo of the phone that is featured. What gets me mad the most is when they have a working demo that only plays the advertisement video and does not allow you to try it out.