Well, in my case ....

I got back into collected editions accumulation when I stumbled across the Barnes & Noble Softcover Masterworks back around 2004, copies of books I had bought as hardcovers (the only available such books) back in 1989-1990 and long since sold off.

Then I found Essential Human Torch at a locl comic shop, the first visit to such a store I'd made in more than a decade. The price looked right ($14.95) for 400-odd pages, but I was surprised when I got it home and took it out of the plastic bag that it was in black and white. At first I felt sort of ripped off, but then I realized this was a way for me to accumulate those old stories at a low cost, stories that almost certainly would never be collected in color hardcovers. I decided, though, that X-Men, Spider-Man and Fantastic Four had to be in hardcover color, but I picked up all the minor lines and the 1970s titles in Essential format.

A few years later I had more disposable income and decided that EVERYTHING should be in hardcover color. Except Silver Age DC, which I was quite content with in black-and-white phone book format.

Now, my preference is Omnibus; if I believe that material will be released within the next year or so in Omnibus format, I will resist buying the Masterwork format.