Well, I'm enjoying the heck out of this show.
I agree that the character's the thing in
Fringe, and that is what drew me in from the get-go. Watching the characters interact, the conflict, all the baggage everyone is struggling with. The supporting characters are just as compelling to me as the main trio. (So sad to lose Charlie in our universe.

I'm still in mourning, I really liked him. It's a comfort to see alt-Charlie in the other universe.) The Walter/Peter dynamic is
so realistic and fascinating to watch.
I love that TPTB began with a long-term vision, and they've been laying groundwork from the beginning for stuff that comes together much later on. It is frustrating to watch a show where it's obvious they don't have an overall arc in mind. All the missed opportunities! I'm glad
Fringe has stayed on the air long enough to follow up on the seeds they planted, and I hope it goes the distance. There's so much left to explore.
Now I'm wondering if Ella will be the key to exposing AltLivia. (Since Peter is apparently clueless.

The force of denial and rationalization could power the universe, I think.)
My husband brought up a question (apologies if this has already been hashed out, we're new to the show): When AltLivia returned to "our" universe with Walter and Peter, I know Bell gave them a boost...but who opened the doorway?