ok thanks for the info. do you need to put something between it and the hotshoe to avoid scratching, or does it come with a separator or some sort?

yes have seen the $45 ebay version, may get that for my X10, but for the X100 i think the original thumbs up is a better lower profile design.

I also have the Thumbs Up for both my X100 and X10. The Thumbs Up slides into the hot shoe just like an external flash unit. There is no piece between the Thumbs Up and the flash shoe. An external flash doesn't use a protection piece between the flash and flash shoe either. As "collierportraits" stated, there is a rubber bumper that is nearly directly under the curved thumb rest that protects the camera body from rubbing against the Thumbs Up.

However, on my X10 I had to shave a very thin sliver off the rubber bumper to prevent the rubber bumper from binding the mode selector dial and making it harder to turn. I know Thumbs Up suggested not pushing the Thumbs Up all the way into the hot shoe, but my natural grip caused the Thumbs Up to eventually go all the way and bind the mode dial. I did not have a binding problem on the X100 due to the mode dial placement away from the rear edge on the camera top.

After the small sliver was removed, no more dial bind. Yes, the TU is costly, but I do get a much more secure grip using it on either X series.