I've listened to a few. They are a bit limited in scope, IMHO because they've limited their characters to a few "old regulars", i.e. Willie, Barnabas, Quentin, Angelique and Maggie with just a couple of add-ons. Individually, I think they all are doing fine acting jobs, although methinks the weaknesses of the original DS show up rather a lot. For example, one has to wonder when Barnabas is ever going to feed? And the character of Quentin kinda screams to give him something to do, otherwise he's just flirting with women and sucking down brandy.
The supernatural threats are genuinely interesting and different from those we've seen before. The last (so far) chronologically ends with a plot hole that I think leaves plenty of room for a sequel...
[spoiler]Quentin and Barnabas are trapped aboard the burning Lorelei, but think about it. Quentin cannot die. Period. And Barnabas could simply vanish and reappear elsewhere, even if he didn't turn into a bat. So Maggie may think them dead, but what are the odds, really?[/spoiler]