I have both a Pentax Optio W30 and Olympus Stylus 1030 SW, and strongly recommend the latter. It's certainly possible that the Pentax W60 addresses some of the problems I experienced with the W30, but it still lacks the shockproof rating of the Olympus, which for me would be the deciding factor.
I owned the Pentax Optio W30 first, but broke two LCD screens over the course of a year (once when I slipped on a steep muddy slope and landed on it while it was in its neoprene case in my pants pocket, and once when I went through a short belly crawl while it was in its neoprene case and tethered to my harness). After I replaced the second LCD screen (at a cost of $65 each to do it myself - Pentax wanted $120 to do the repair!), the waterproofing failed when I dipped the camera just below a water surface. Although I immediately disassembled the camera and thoroughly dried it, it now has a short of some type that causes it to completely drain the battery in a day, even while off.
I then purchased the Olympus Stylus 1030 SW, on the basis of the added "shockproof" rating. Several caving trips and submersions later, it is still functioning perfectly. I have found the Stylus 1030 SW to be a much better caving camera than the Optio W30 on several other fronts as well - it's much more responsive, the overall picture quality is much better, the autofocus works far better in low-light conditions, and low-light framing is much easier because the Stylus' screen "gains up" in low light. I also like the fact that the Stylus has an LED that you can use for super macro work. You can even have the LED on while the camera is off, so:
"It's not just a camera, it's also a tertiary light source!"
The only feature on the Optio that I miss on the Stylus is manual focus, and the much better low-light autofocus largely addresses that problem.
Obviously no camera can be expected to survive being exposed to true caving conditions for very long - I now use a small Otterbox (still small enough to fit in a pocket!) to protect the Stylus when traveling through caves.