I have been doing some research, trying to determine the most useful types of tools for various survival situations. A Rip Hammer is (obviously) capable of hammering quite well, the claw can be used to dig reasonably well (better than a stick or a knife, especially with the handle and the ease with which one could sink the claw into the ground). The claw could be mildly sharpened so that it could be used to split wood or even hack off larger limbs (going at it from more or less one end or the other, as opposed to directly perpendicular) if a hatchet or axe is unavailable. The Hammer can obviously be used reasonably well as a non-lethal (with less forceful blows) or a lethal last-ditch defensive weapon. Finally, it can pry (that's pretty much what it's designed to do).
The first four of those properties could be more useful in wilderness survival, though a small shovel might be better for the things actually needed. A small shovel could obviously dig better, but it could still be used for the mild hammering one wold need for the outdoors (breaking nuts, tapping stakes, etc), and could still be used as a defensive weapon. And, if one edge is sharpened, would likely be better at chopping and splitting than a hammer with a sharpened claw.
However, for urban survival, a hammer could be much more useful at smashing through obstacles (duh) to evade threats or reach resources. Padlocks could be hammered open, glass could be shattered (with relative ease, at least), or even wooden doors or boarded windows could be busted. And the prying side could be used to help open doors without destroying them (or if its too tough to smash through, like a nice wooden or steel door), or pry back a convertible car's window to unlock the door.
Finally, if the tool is kept at one's side all the time, and especially if a small container of nails is kept in the pack or close by, one could easily put a few nails into a door or window (or into some boards over said openings) for reinforcement. That last detail could also be useful in wilderness survival for easily putting together more durable shelters or whatever.
These are the reasons I chose to replace my 20" steel baton with a hammer, because while the baton can do some of these things with mild effectiveness (hammer, for example), it is still primarily a weapon. Conversely, the hammer is a relatively versatile tool. I will probably get something like a pill container to fill with nails.
Oh, this is the hammer I have:
The head is 22oz and overall it weighs 2.5lbs.
What do you guys think?