LVM is partition manager for the local hard drives and the "cluster" support (CLVM) is not fully integrated in the LVM model. Also, LVM only provide you the Volume api, not the filesystem.
And Lustre was designed as scalable cluster (distributed) filesystem, and also it have POSIX File API support.
If you need scalable solution, or file access API, choose Lustre.
If you builds small cluster (not more dozen computers), and you will manage volumes, choose LVM.