Soma Grand is a good property. If you're looking at it from the standpoint of an investment, right now that could be good. Most prices for condos south of Market street are competitive. My question to you, Isabel, is whether or not you are actually an "investor" or if you're looking to live in a home in San Francisco (which is different in how you view buying)? As an investor, you probably will want to put more than 20% down on your loan so that if you rent it out you have a better chance for cash flow, and you'll probably want to sell it in about 2-3 years at some sort of profit - hopefully the most profit possible. As a homebuyer, you'll probably have just about 20% down, and you'll think about living in the home for about 5-7 years - or until you need to move (for work, or building a family, or into something bigger etc.).
The next 2-3 years don't quite seem to have too much strength in being able to predict what will happen. No one can forsee what (and if) kind of profit you'd see in that short of time with this difficult economy. Appreciation on many properties right now is in question.
The next 5-7 years are equally as tough, but past experience shows that homeowners that live in their properties for this amount of time see some sort of good appreciation.
Soma Grand is in a neighborhood that is still developing. Trinity towers is being built right next door, and most of those units will be low income and market rental homes with shops and a mall on the main floor. The area is looking to improve over the next few years, but even then I feel it will lack a "walking" neighborhood feel. If you cross market street to Hayes Valley and the Civic Center area, there are other developments that have been built in well developed "walking" neighborhoods, which some think are safer.
Good luck out there, and remember to take your agent with you when you visit the new developments.