I have used both LVM and non-LVM. I currently don't choose to install it on my desktop or laptop computers. I admit to not being the biggest expert on LVM, but I don't think my choice is irrational.
* I often move my old partitions to a new Linux distro. Since the initrd / initramfs / etc code gets rewritten approximately every release, porting a complex setup is painful. On the other hand, just mounting a partition is easy.
* If you use something like RAID0 (I forget what LVM calls it), and one drive fails, all of your data is gone. "Too big to fail," unfortunately doesn't apply to volume groups. I'm sure there's a way to RAID5 it, and so forth, but then you have to start worrying about things like whether the drives are the same size, what is the correct stripe size to use, whether write barriers are fully supported on your configuration, and so forth. Again-- if you value your time, simple is better.
* If I really need to change the size of an ext3, ext4, etc. partition, the gparted boot disk can do it easily. I can even move partitions with dd or rsync (although that is rarely necessary.)
* Sometimes I even have to give more space, or take space away from, the OS of the Beast (yes, I still have one computer that dual-boots.) LVM can't help me with this-- in fact, it hurts severely, because gparted can't resize a partition which LVM is managing. So if I forget to uncheck the LVM install checkbox on my dual-boot PC, and I need to shrink the Windows partition, I'm screwed.
LVM makes more sense in a server environment, I think. Of course, even in a server environment, you often have things like RAID cards doing this kind of thing for you. Like everything else in storage, at the end of the day, it really depends on your use case.