I would summarize things as follows:
Given the same distribution (issuance),
the energy cost is going to be same no matter what
scheme you use, but PoW is the simplest, most
proven, and arguably the most fair.
I've seen you mention that before but can't quite wrap my head around the notion that PoS will use a lot of energy. Can you give a scenario?
It's explained in this article:
http://www.truthcoin.info/blog/pow-and-mining/It depends on implementation of the coin, but something like making
alternate chains or addresses...spending CPU power to compete for
the rewards until its no longer profitable to keep doing so.
This is completely clueless. A simple block production bond system makes it unprofitable to ever attempt to produce blocks on more than one chain at a time. This is actually yet another permutation of the naive nothing at stake "problem" that has been solved ages ago by DPOS.
It's quite amazing that people are so emotionally invested in proof of waste that they continue to cling on to these non-issues in desperation.
I'll refer to the article again:
switching the payout-trigger to a social or political dimension (as in Delegated-PoS) would merely transpose the work-expenditures correspondingly to the realms of bribery and propaganda, which Bitshares has already seen.
https://bitsharestalk.org/index.php?topic=6096.45The bottom line is: if there is money to be made,
people will do whatever is possible to compete for it.
You really can't stop competition and people trying
to game the system in some way.
To put it more concretely with DPOS: If Bitshares
really took off and was generating a million dollars
worth of rewards everyday like Bitcoin does now,
don't you think people would be trying to become
delegates? Don't you think certain motivated
people or groups would try to get 5, 10, 25, 50,
or more of the delegate slots?
What would stop them from investing money to
do so, given that the payouts would be enormous?
Furthermore, why wouldn't a delegate re-invest
his profits into trying to acquire more delegate spots?
On a side note: Security deposits may solve an aspect of the "nothing at
stake" issue, but they do not stop competition.
Ok, you cannot possibly be that ignorant, being around this long. 
