I have an older copy of Pro Tracks (2.2, came with my DigiTech floor processor). It's not much but it gets the basic job done. From the looks of it, you have pretty much all the most basic functions. You can record audio (only up to 16 tracks) and MIDI tracks (unlimited) and put effects on them (I think it just comes with the crappy generic Cakewalk FX). The routing looks a little less flexible than in Sonar, but maybe I'm just being fooled by the different interface design. VST plugins are not supported, but it has DXi support (and includes one softsynth). If it's all your have, it'll get you by just fine until you upgrade to one of the 'big boys.'
I don't have any experience with Cubase LE so I can't really help you out there, but I would guess the features are roughly similar.