I have used and still do use both Lubuntu 11.10 and Mint 11LXDE on different computers. For all practical purposes they are the same. Lubuntu comes slightly leaner, you will want to add startup manager if you dual boot, apt-xapian-index to get the nice search tool in Synaptic and Ubuntu Software Center if you want an alternative to Synaptic. The advantages for Lubuntu are a 64-bit install, quicker kernel, etc updates, my wine applications always perform flawlessly and the Ubuntu Software Center actually works. Mint LXDE software center freezes about one out of every three times while typing in the search box and 2 of my wine applications often have to be killed to shutdown. Also, Lubuntu 11.10 has the 3.0xx kernel which Mint 11 does not, but I think Mint 12 LXDE does.