I've visited a few other DZ chapters aside from my own. Sometimes they knew I was coming and other times, I just stopped in without notice. All of the girls have been very polite and were glad to show me around their house, no matter if they expected my visit or not!
As for differences in the girls, I didn't notice much of a difference. Of course, I usually didn't stay longer than a day (in most cases only a couple of hours), so it's hard to get a good impression of someone without knowing them for a while. However, I was never disappointed with any of the girls I met, and they were all very nice and "sisterly" to me, which made me very proud to be a Delta Zeta.