I like the dcx way alot better because:
You insert controls directly on to the dialog, its important you have a general idea of what you want with dcx since you can embedd and embedd and embedd etc etc lol. But creating the controls is more important then fixing the x y w h in the creation command. Using Cell layout algorithm you can ensure propper alignment and resizing. Its not just better because the added feautures its way better in the way you retreive and send info to it.
Of course a DCXStudio would be hot, i agree.
i've finished the comparision for those interested:
http://www.i-mirc.com/dcxcmp/dcxvsmdx.htm
