Union Square Primer:

http://www.sfgate.com/traveler/guide.../unionsq.shtml

Lots to see, do, eat, and drink.

If someone panhandles you for money either ignore them or say, "Sorry, no".

I've never had anyone follow me down the street or shout or try to touch me.

You should know which direction is the shopping district and which direction can lead you into the Tenderloin. Try this graphic to get your bearings:

http://www.sfgate.com/traveler/graph...nionsq-map.gif

Sadly, most of the theaters are on the badder side of the neighborhood.

I've seen many responses indicating the financial/embarcadero area are too quiet and desolate at night. However, what if we were to stay at either the Hyatt Regency Embarcadero or the Mandarin, but we are planning on eating dinner in some of the more vibrant areas. As I understand it both these hotels are convenient to the cable cars, so we wouldn't have to walk at night. Wouldn't it be an advantage to be in a quiet area so we won't hear noises from outside? It seems like we would be less likely to encounter homeless people at night. What do you think about staying at these hotels?

Call me skeptical but I'm betting that it's the same person using multiple names who keeps posting the URL's for the anti-Union Square stuff.
Always similar URL's.

Makes me want to spend the night *in* Union Square just so I can come back and write about it!

While there may be some pan handlers in the area - I can assure you that most of the drug-dealing in San Francisco doesn't happen there. You're more likely to see that kind of stuff at the 16th and Mission BART station -which ironically has a police kiosk near it.