I am looking at 3 SDK's for cross-platform (iOS and Android) development.

So far narrowed it down to:

http://www.coronalabs.com/products/corona-sdk/

http://giderosmobile.com/

http://getmoai.com/moai-faqs.html

What I'm looking for is this:
1 - works for iOS + Android

2 - free as long as I don't make money - if I have to pay when app makes money, that's fine. So for example Corona's 100k revenue limit on free version sounds fine

3 - splash screen is ok

4 - language doesn't matter, they all seem to be LUA, but it's not very relevant, I would just like to write code once instead of multiple times, and also I'd like to make use of ready packages, than coding everything from scratch.

I believe I can chose from any of those 3 based on my requirements. Perhaps there are other differences I should worry about?

Is one platform has more bugs than another? Is one getting more support, and others are no longer in development?

Any suggestions which one to pick? or perhaps there are more than just those 3?

I have been working with Corona for a while and I find the APIs very straight forward, and they are always improving on what is already there, and the forums / community is extremely active and helpful. If you are concerned with costs there is http://cocos2d.org/ which I believe is completely free and uses LUA similar to many of the other SDKs for mobile. Another route would be to go with Unity and utilize the 2D kit that is available, more expensive when you want to go and publish but their framework is tried and true.

I have been enjoying working with Corona, and it is free to start, so my point goes to Corona if I had to choose one. Even when you want to publish the cost is minimal compared to some of the other SDKs out there.

Another vote for Corona here. I've got an app (Predictive iDash) and a game (Goofy Cubes) published using it. There are a lot of good 3rd party tools and APIs for it, too, like the Physics Editor, Particle Candy engine, etc. As JustAGuy said, good support community, too.