As we know we can upgrade to Mac OS X Lion from Snow leopard 10.6.8.
Once this has been done, can we recover Snow Leopard again, or do we have to reinstall Snow Leopard?
Additionally, can we install Xcode 4? My main concern is if we can continue development with a lower version of Xcode or if we can only use iOS 5.
If there is any link to compare both operating systems can you please share?