In a rewatch
I used to watch all of the CSIs when Miami and NY were on the air. I stopped watching Vegas when Grissom left. I couldn't stand Langston's character. Anyway, I really liked NY while it was on but I'm finding it difficult to watch now. Most of the acting was okay on NY but Hill Harper and Melina Kanakaredes were just awful. Harper, over acted his way through the entire series. If you are watching again on Netflix or on syndication, pay attention to how he works with trace evidence. His mannerisms and faked intensity are so over the top. His dialogue and interaction with other characters wasn't terrible but when he is alone I find him so unbelievable to the point that preposterous is the only word I can think of to describe his character.
As for Stella, a lot of my issues have to do with how the character was written. With her it was non stop emotionalism and one liners. The acting was passable for the most part but she sucked at delivering one liners and that just grated. I get that CSI is famous for their use but why would the writers/producers keep giving them to someone who just sucks at it? Her timing was terrible. Look at Caruso. People either really liked his character or they hated him. Most people though acknowledge that even though his character used one liners far too often, he almost always nailed them.