Take a look here for a description of the differences between LDOMs and containers.

We think that we have good reasons to use LDOMs. There are some logical breaks in functionality in our application - online processes, user front end support, overnight batch etc that lend themselves to spliiting onto separate machines and these could be LDOMs or zones. We also have third party software that's licensed on a per core basis, so by running this in an LDOM, we could reduce our licence costs from 8 to 1. As zones share an OS and LDOMs each have their own, there are patching considerations. Also, using LDOMs allows us to share a production and development environment on the same hardware. The question really is, are there positive reasons NOT to use LDOMs?