I'm coming to the conclusion that the answer is.... "mostly not".
If you scroll lower down this page, you'll see that I held off until Lightroom could support the X10 files, which it now does. But I'm a little underwhelmed. Fuji are pretty good at producing decent JPEGs, and the noise in the RAF files (of which there is more than people might think) is harder to deal with than I've experienced with my other cameras.
I've done some comparisons at various ISOs and it is certainly the case that with standard noise reduction settings, the raw files are more detailed than JPEGs - more so as you go up the scale, so the default noise processing in the camera is quite strong. However, for M size images (which may be where this camera performs at its best), if you turn the JPEG noise reduction to its lowest setting, you'll find that there's precious little difference from the raw files in terms of detail, and the noise left in the image is still at a low enough level to be acceptable - at least to me!
A few samples. First, at ISO200, JPEG first:
And same again at ISO800:
I haven't posted higher - I don't expect miracles above ISO800, and you need to choose what's more important to you - noise or detail - because with a small sensor it's difficult to have lots of the latter without some of the former. It's also interesting to note how colours are cooler in the JPEGs (on occasion the raws are more appealing) and that ACR does some funny things with the image size.... you lose a bit around the edges.
However, there are some circumstances where raw may be worth a go:
(1) higher ISOs with L image size - if you work hard, I think an ISO1600 processed raw file from the X10 is likely on occasion to be an improvement on the JPEG - I need to test this further.
(2) when the JPEG's blow the red channel under certain (energy saving) lighting conditions. There are a few occasions when I've found that the X10 JPEGs handle reds horribly - turning them a nasty shade of pink in the process. It's only the JPEGs though - the raw files taken at the same time are much closer to the real thing. Hopefully fixable in a firmware update if Fuji is listening.....
Some early raw files to download and play with:
When I first go the X10 I loaded Silkpix and had a go, and decided that until ACR can support RAW files from the X10, it's going to be JPEGs for me - the Silkypix raw file converter supplied with the camera is pretty feature-packed but horrible to use for those of us used to Lightroom.
That said, I took a few shots of a hastily put-together still life, ranging from ISO100-1600, each taken as RAW plus fine JPEG. If you want to download and have a play, please feel free. Here's one example of the scene - ISO1600 converted in Silkypix with a few more adjustments in LR3. I can hardly believe that compact cameras have come on so far that a picture like this is even possible at ISO1600! I know that the X10 isn't the only one capable of this, but impressive nonetheless (click to view larger):
All images were taken on a tripod with self timer, and in deliberately poor-average lighting conditions in order to replicate the reasons for travelling up the ISO scale. I also took care to make sure that the histogram showed no sign of blown highlights when taking the photos - however, on my computer there's definitely some issues in the red channel, which will need further investigation.
Here's the link. Beware, this is a very large file!
Zip file with RAW and JPEG images for comparison