Well you should seriously rephrase the question. It looks like subjective.
I'll just give my experience with all these tools.
Disclaimer:- The following review is my own personal opinion and involves my personal experience. You might have different opinion.
Marmalade
While I've used marmalade for most of my deployed projects, I've never used their RAD tool quick
for any serious development. I was asked to try it out by remaking one of our deployed game. I was really impressed with it's quickness and less-verbosity. Although it was only for 2D and I recommended it's use over normal marmalade for all our 2D games. Unfortunately, we never made any 2D games after that. The benefit was that it comes preloaded with box2D and Cocos-2Dx and still supports C++ libraries. Didn't try EDK with it yet, but it should support that too. The con (for me) was I had to learn luascript for that.
Flash
Well I am not a flash expert here, but I tried it on two of our deployed game and it was a good one. Although it was too limited in what it seemed to have. We had to Re-code one of these games in marmlade, just to support some 3D elements, which were not possible to do in flash(at least for me). Flash was too verbose and too confusing for me, since we don't know where the actual script is attached. I guess it must have happened with all programmers who tried flash after trying any other tool, like marmalade. It just confuse you.
Unity
Well it was much much better than Flash, and is actually a well written game engine. Although it might cost a fortune for Indie developers, but still it's worth it. I've been using it for almost 4-5 months and I already started liking it over any other engine. It's easy to learn and too less verbose. You just need to drag and drop and attach the script to the gameobjects.(Not really that simple actually). No need to worry about Physics engine, no worries about plugins(since most of the plugins are already avaialable). And you can do 3D in that too.
Never tried Corona and HTML5 for any development project, so can't have a say in that.