Dont get it!  why is 123,  so incredibly messy when it comes to editing, model-releases, etc.  I would have thought that making things like these an easy-business is a must!
Their attach- releases, is also done in a weird way, sometimes it works, sometimes it doesnt?  why cant they just change this stupid system and incorporate more modern ways.

123 is really simple. I don't understand actually what is messy and confusing there. I never had problems with their submission system. Regarding editing, you only have description and keywords. (the same as SS), and no categories. When you put description and keywords, you just click on the link on the top that says "Sell Images" and there, in the middle of the screen, you will see a button that says "releases". Click it, choose the release (releases) that you need, and click the button that says "attach releases to photos". New page will open with your newest images showing first, and you just have to put a checkmark under all images that should have MR attached. That's all.

@eggshell, click the button "Sell Images" on the top of the screen, and then click on the button "download" in the central part of the screen, on the left. Here you will see the list of your recently sold images.