I have a UXDV-3 video camera and would be happy to give you my opinion on it.
The actual underwater housing case is very well made with double seals and is very compact since its built specifically to fit the Ultramax camera. The good thing about this is that it makes for a very compact package. The bad thing is that you are pretty much tied to the camera that comes with it which can be a pain if it breaks which all electronic items seem to do eventually. (This is what happened to me my Canon A570is and Canon underwater case. The camera breaks and costs more to fix than it was new so I just stock up on these obsolete cameras on Ebay anytime I see one come across). The mirror image of the screen on the fold out viewer takes a bit of getting used to but you really can't see the image in the mirror underwater anyway except in extremely bright light or shallows so you just get used to pointing in the general directly of what you want to shoot and that seems to work fine. After a while, I found I really wasn't using the display at all. The buttons are easy to find and operate underwater, although the main thing you will be doing is turning the record feature on off underwater. I really wish they had made this case to fit a wider variety of cameras but even within a particular model, the manufacturers change the button layouts and size with every model change so its sort of a losing battle all around.
The camera itself is a 720p HD camera that is actually made by Aiptek under their model number V5ZH5 which is now obsolete. Aiptek makes and updated camera but I don't know if it will fit this case or not. On the plus side, this camera uses a standard lithium ion battery so its cheap and easy to keep several charged on hand and the battery life is more than enough for a long dive. In the version of the firmware I have however, you have to turn on the camera before putting it into the case and there is no standby or sleep feature. I've contacted support about getting a firmware upgrade but the company doesn't really seem to have much in they way of support online or otherwise, although you can check out their website for manuals. My biggest gripe with the camera is that is doesn't have image stabilization. The still camera setting (which you will never use) has this feature, but not the video setting, which is very unfortunate since its very hard to hold any camera steady underwater. The zoom feature works great out of the underwater case but its mostly useless in the case since the autofocus doesn't seem to work though the thick plastic, but you probably couldn't use zoom much anyway without image stabilization. The image quality is surprisingly good and I use a 16 GB SD card which can last you a whole week of dives. For the money it costs, I'm happy with the camera and do not regret buying it. I have the lights setup as well but have only use the camera in the daytime so far so I don't have any experience with that setup yet but I'm going to Bonaire in a couple of weeks so I'll try it out there and let you know how it goes. The lights seem well made as well and I like the fact that the battery compartment is sealed from the electronics so even if it floods, it shouldn't ruin the light.
The net of it is that for the money, it would be next to impossible to find as good of a camera and underwater case setup that gives you HD video. The negative things to consider are that you are locked into a relatively cheap camera with limited features, and have questionable support from the manufacturer.
