HANDYCAM  I downloaded this with high hopes that it might provide a new angle on masking images.

However, it offers nothing that you can't get in Photoshop or Elements' extract feature. AFAICT you just paint out the mask and/or paint in the stuff to keep. There is a brush for painting the transitional pixels as well.

However, I see no real savings in time not increases in quality over using a real masking program. I could even do a better job in the Gimp, for free, if all it offers is painting on a mask.  
(Version 1.0.2)

IANGREIG  I find that Decompose scores over Photoshop by having a brush to define the transitional edge ares where pixels may be foreground image or background.

A cut-out in PhotoShop relies on performing a very accurate selection, knocking out the background and then doing a lot of smoothing of the edges. In Decompose you make a broad-brush selection of the edge area, covering the whole border between foreground and background, from which the app. calculates which is which, removes the background to transparency and gives a smooth edge.

It seems to work well even if there isn't a lot of contrast between foreground and background. If you can see it, you can cut it out.

Well worth the money to save time and effort -- and if you need to make good quality, foolproof cut-outs in a hurry, you'll thank the developers.

I think some sensitivity controls would help, and I felt the need of grab tool with a spacebar shortcut to navigate around the image, but this is only a v1.n application and these are only minor refinements that are bound to come in future releases..  
(Version 1.0.1)

ALAN  In my opinion, Decompose has got a great potential, and its results are too good to stop developing it.

Bravo!  
(Version 1.0)