We used Corona SDK, specifically the Starter Set, for our first game Messimage. For the game development itself it's very good and very easy to learn, easy ads integration as well if you want to monetize straight away. The starter option is free. However, there are some negatives to using the Starter set and also the Basic set (at $16 per month) which I have found undesirable. For starter set, no in-app purchases is supported, you'd have to get basic at least. One of the biggest negatives that I found was there was no support for Android share intent where you can share info from your app to other apps in your phone (unless you get the Enterprise set at 200/month). This is useful for social features such as sharing to Whatsapp, LINE, etc. Facebook share is supported though and for twitter you can use third party libraries.
I'm looking to shift to Unity which looks very interesting.