Bitshares delegates, on the other hand, will most likely build dedicated infrastructure to establish direct communication channels between active delegates and to enable transaction speeds that are simply not possible with (a) a non-deterministic solution or (b) a solution dependent on low computational resource requirements.
This is, of course, because there is quantifiably more centralization to the protocol. It's very easy to imagine the perfect world where none of those delegates are corrupt and always have the best interest of the users at heart, but reality is reality. And those in power have learned quite a lot about how to make people believe that their way is the best (or only) way, especially with the false dichotomies that are so rampant in politics.
That is not to say that Bitcoin or Ethereum or Nxt does it better, but there are tradeoffs everywhere.
The only thing a corrupt delegate can do is choose not to sign blocks in bitshares. This means that any number of corrupt actors working as delegates would be noticed very quickly as they begin missing the signatures of blocks...which will mark them for being voted out of the top 101 relatively quickly. I believe Bytemaster (architect of DPoS) said that even if 90% of the blockproducers attacked the system in this way, the speed of transactions would only be reduced by something like 50% (so you would be looking at 20 second transaction times...until new delegates came in).
As for proving one's worth as a delegate, there are many job positions a DAC requires filling, which means there will be different metrics for kind to go through.
For coders, there is Github.
For Media, it is apparent.
For Marketing, (we are working on this one).
For Community Services it is also pretty apparent.
The largest stakeholders are naturally going to want to police their own investment and so over time, I believe you will have trust built into everything. I also believe that those wishing to become delegates at high marketcaps will serve as police to show people when a delegate is providing less value than they. They will also likely be willing to prove it by working for free along side the delegate to prove its efficiency.
Ultimately I have yet to find a more flexible framework. NxT would be my next in line in terms of interest. Ripple and Stellar would be too if the system was a little more to my philosophical leanings...but ultimately I fear both of these becoming foundations for the new economy. As far as Ethereum goes...really hard to tell until they provide us with something resembling a real product.