I can only speak for the E900. I've owned one for 1 1/2 years, and have done a couple of week long carribean dive trips with it. I don't own an external strobe (yet) and have only used the on-camera flash.
I find shooting RAW to be very beneficial. My first couple of dives with a camera I shot jpg and was not happy with my ability to adjust the white balance in photoshop afterwards. Macro shots taken with the on-camera flash were fine, but anything very far away did not come out very good. I have since shot RAW on every dive.
Probably the main down side to RAW is the write time for Point-n-Shoot cameras. My E900 takes 6 seconds to write the 18MB file, and then the flash recycle time is on top of that too if you are using flash which makes it around 10 seconds between shots. I don't think it's ideal, but for me its worth it for the post-processing adjustablitity. If all you shoot are macro shots that the flash can light adequately, then JPG would be just fine.
The next major down side to RAW is that every image that you want to keep will have to be converted to some other image form. A blurry jpg or RAW is the same thou, you just delete them. I personally like doing the editing, and find that it doesn't take that long once you figure out what you need to adjust. Some people hate it thou, and for them I wouldn't suggest bothering with RAW.
The large file sizes will limit the number of images you can fit on a card. A 1GB xD card will hold 54 RAW files, and the 2GB xD can hold 108 images. This is fine for me for 2 dives. The longer write times make you be a little more carefull with your first shot and doesn't really allow you to take a bunch of shots of a fast moving fish.
I'm not sure what RAW problems Larry C and DesertEagle are talking about. I use Adobe Camera Raw and it works just fine. I've also used S7Raw and some other programs based on DCRaw and all work just fine. I have looked into Bibble and another program whose name escapes me and they didn't support the E900 thou.
The E900 is not the perfect camera by any means, but it's a pretty good deal right now. I picked up a second one a couple of months ago for $154 after the $50 Fuji rebate.
I'm sure there are many better sample photos out there as I'm relatively new to it all, but you can see some of mine at
dehokens' photosets on Flickr . All were taken with my E900 with on-camera flash.
Good luck in your camera quest.