Here are some Con's to consider:
- you're constantly surrounded by concrete and a decent amount of traffic
- despite some "nice and active" parts of SoMa, there are many many blocks that are quite shady and populated by homeless people at night (and day sometimes). Anything past 5th street and also near 1st and 2nd & Harrison are some of those areas.
- if you like access to some good road biking or running on trails, SoMa is not a great place to live (consider Marina, Cow hollow, Presidio in San Francisco (or North or East Bay)
- you'll suffer from the daily 80-bridge traffic and Giants game traffic on game days