I finally saw Two Towers. ***SPOILERS****
I thought it was great. I don't think the Ents were a let down at all, and there were way more than 6, unless you saw a different version than I did. The battles were great, I loved the Wargs, Mordor looked awesome, I liked that they are setting up Arwen as a character, the Elves coming to help was a great addition, and of course Gollum was spectacular.
The complaints against Faramir seemed unfounded, since he did end up resisting the ring and letting them go. I thought his character was faithful to the book. I wasn't certain he'd let them go in the book, either.
My biggest complaint would be how Theoden's "possession" was handled. I didn't think he was under any spell in the book, just weary, beaten down, and overly dependent on Wormtongue. I thought Gandalf just talked him out of it without using any scorcery, which I preferred.
Also, why didn't Gandalf have Glamdring in the movie? He's much cooler with a sword than a staff.