The default is the minimum version that Corona supports, which at the time of this posting is…
API Level 10 (Android OS version 2.3.3)
I highly recommend that you do *not* change this and leave it at the minimum Corona supports. This is because the Android market is very fragmented. So, the more Android OS versions you support, the more customers you will have and potentially the more revenue you’ll make.
The debatable question out in the wild is if a device running a newer Android OS version is a better/faster device, which is why we’re making this an option now. In my opinion, it’s wrong to assume that a device running a newer OS version is a better device. Cheap Android devices are popular and learning to work with low-end devices is just something you have to learn to deal with. The same can be said about desktop PCs. Upgrading a crappy low-end PC to use a newer Windows version won’t make it magically run faster and with more memory (usually the opposite happens).