The issue with SSB vs. sat. phone for offshore use is basically the same as cell phone vs. VHF for near coastal cruising. The phone can connect you directly to one person, but the SSB will allow you to put out a more general call for assistance.
The bigger question is if you go with a sat phone, which service do you use? Globalstar is almost useless with service only a few minutes out of each hour and Iridium is very expensive. Maybe when Globalstar gets some more satellites up it will be worth a second look.
One advantage to the sat. phone is that it is relatively small and portable, so you can use it off the boat as well. My brother, for example, uses his while offshore fishing, but also when he is back country skiing in the winter.