I've had a few positive experiences with some of the top Witnesses. They've engaged in discussion and acknowledged comments, even if disagreements were present.
Others...eh, not as much of a positive experience. I've observed that some seem to post incessantly, rewarding themselves on top of their daily producer rewards for maintaining the blockchain. When is enough, enough?
Even worse, I had a Witness downvote me recently on the erroneous assertion that I cited "false facts" in a comment I made to a post. When I defended myself with objective and verifiable citations regarding what I wrote, there was no response, and the downvote remains.
Wouldn't it be nice if we could all delegate a portion of our Steem Power holdings and maintain the blockchain via our stakes, similar to how other delegated proof of stake systems work? I would imagine such a system would be more equitable.
Alas, such a system doesn't exist here. I have not yet voted for a Witness but it seems the time has come to do so, as it is apparent that the future success of the blockchain is heavily swayed by those in this position of influence.
RE: I completely agree with @riverhead.