I've played all the Legacy of Kain games. Blood Omen, Soul Reaver, Legacy of Kain 2, Soul Reaver 2 and Defiance. Defiance is a good game but it's lacking in many things, like both characters get controlled exactly the same way, when you use them it's more like playing the same character who looks different, nothing much changes between them.
Gameplay-wise it's a good game, not the best in the series but still worth a play.