I haven't studied this. Is Ethereum going the Dash masternode or Bitshares DPoS route of the rich get richer and usership disappears?
It's supposedly going similar to the Darkcoin route, except with an automated delete your collateral for misbehaving mechanism to try and negate "nothing at stake". Ethereum Casper and Tendermint seem identical so most pros and cons will apply to both.
With most traditional PoS systems, the big holders just get more mega wealthy over time. In the DPoS system, block validators don't collect an infinite number of fees as the network increases transactions or anything. Delegates set a burn rate % to decide how much of the transaction fees to destroy. In other words, delegates set their own pay rate and stakeholders can either vote for expensive delegates or vote for cheap ones and receive equity gain/stock buy back mechanism via the burn.
Elements of the DPoS system are both ingenious and stupidly overly complex all at the same time. It's designed for maximum vertical approach, while I think Vitalik wants to attempt to turn this Casper thing into a partitioned network eventually. In a collateral based system with a fixed rate, the working set of validators is inherently designed to decrease over time unless collateral is set trivially low, which it cannot be for security/functionality reasons. Combined with the DAPP overhead, Casper would probably have more centralization than Bitcoin. Bitcoin usually just appears on the surface to be overly centralized, when in reality, it's not because of all the transient miners, which Ethereum would not have.
Unless it brings you extreme problems in state recovery, I feel like a fixed number of block validators using a variable collateral bid system is superior to the fixed rate collateral system.