I'm so glad to see this series coming back into print. They are well-plotted and highly suspenseful, but I still own and re-read the originals after almost 20 years mainly for the characters and their relationship. Fiddler and Fiora are smart, strong, determined people. They have integrity, though Fiddler in particular tends to care more about what is right than what is legal. Fiddler is in some respects the classic alpha male, but he doesn't ride roughshod over Fiora - and she'd cut him off at the knees if he tried. They have enough in common and respect and understand each other so well that the bond between them is powerful and believable, but they have enough differences over things that matter that their conflicts are powerful and believable as well. Secondary characters are vivid and fun, too. Or vivid and scary.
These books are on the edge of my tolerance for gritty realism, but my tolerance is low. There's violence and betrayal and corruption, but it never feels gratuitous. In fact, it's the reason Fiddler does what he does.
The series starts out well and gets better and better. Recommended highly.