The main difference that I can see is that the HSU has a much larger center channel to help with dialogue and make the system "blend" a little better. Both are excellent and well reviewed.
Note that the Take Classic is not sold with a subwoofer anymore, so there is nothing stopping you from mating the Energy Take satellites with the HSU subwoofer. The HSU subs will be better than any of the entry-level 8" Energy subs.
Here is a pro review where the HSU package is directly compared to an Energy package... although the Energy speakrs are the ACT6 and not the Take Classic, they should be similar enough that you can get some ideas of the pros/cons: http://www.soundandvisionmag.com/spe...-a-budget.html