Lubuntu is at least a variant of Ubuntu while Elementary is not. Elementary's main feature is basically that it's Linux that looks like OS X.
TBH, though, OS X is already a BSD variant and I typically find people who make good use of OS X are proficient at the terminal, which is a great advantage over Windows' (almost-)everything-is-a-GUI approach. Since Linux has the same terminal - Bash - you don't really get too much from that alone. (Sure, you can install other shells like CSH or ZSH but the default is Bash.)
If you want to try it out, I'd suggest Lubuntu over Elemntary OS but really the differences are just window managers. Ubuntu is Unity, Lubuntu is LXDE, Xubuntu is XFCE, Kubuntu is KDE, Ubuntu-Gnome is Gnome, and Ubuntu Mate is Mate. Shocking, I know. I do prefer Xubuntu over Lubuntu, but really just look at some screenshots to see the difference. (Default programs also change though, so there's slight differences in that but you're also free to install whatever you want since they share the Ubuntu repository.)
The other thing to note is that you can, and should, install Virtualbox and just run a virtual machine with these things to try them. I have a feeling you won't find anything compelling to push you away from OS X, though there's plenty compelling to push someone wanting more powerful software away from Windows.