My experience of using a few different DC blockers is they seem to choke the transient impact, bass and speed of the power amplifier.
If you have DC issues, like I did in my last apartment, they can make the sound cleaner and clearer, but with the above mentioned negatives. So they give and take away.
If you have no DC issues, like in my current house, they just become a net negative and your system is better without them.