I have not tried it, but everything I have heard leads me to believe that "D. Mercer" is mostly right. I would not base my buying decision on UV presents. Use the quality of the movie (critic and public reception, etc.) and the quality of the transfer (technical qualities of the the audio and video). This is a "last gasp" by Hollywood to keep their death grip hold on the crappy media business.
Yes you can still play the dvd on your regular player. Dvds are more and more often being packaged as a set of multiple formats in order to sell more copies. For instance you can get many Blu-ray packs that also include a regular dvd and a digital copy. A standard digital copy is one that you can download and store on your computer. Most of these are downloadable in either quicktime (apple) or WMV (windows) format. Ultraviolet uses a proprietary format that requires you to subscribe to the service and install their program in order to watch your digital copy.
My personal opinion is that Ultraviolet sucks because you do have to install their software and open an account with them. The other types of digital you can just download and watch with any viewer that is capable of handling that format. But if all you want is the dvd then it doesn't really matter what format the digital copy is in.
The answer is NO. You cannot play a Blu ray disc on a DVD player. There is a difference in the light ray used between the two. Also, with computers, the standard tower always has a DVD burner/reader, but you can also purchase these to include blu ray functions as I did several years ago, thus enabling downloads from blu ray discs and enabling creating your own movies on a blu ray format.
>>>> Its a ripoff, dont expect anything more than some 200MB movie file that will look like garbage on anything larger than a 3" cell phone. <<<<
But you still have the DVD (or BluRay) version, too.
The UltraViolet copy that you get IN ADDITION to the regular version is an extra, not a ripoff, and it is good for exactly what it is intended for, and makes no difference to the DVD or BluRay that you are buying the package for.