I think Conan is still largely the same, and he's always been my favorite. I saw Fallon the other night, and he was just horrible. His "jokes" were horrible and nervously delivered. His interviews are awkward as all hell. Maybe that's just his intentional style, but I don't find it cute or funny in any way. Ferguson sucks even worse. It's like his writers deliberately avoid putting anything remotely humorous in the show.
Conan's monologues are pretty consistently funny, but there's always the punchlines that just fall flat, and he's kind of like "they made me do it" about it.
Also, does anyone get very distracted by the backgrounds in these shows? Conan's new set is the most distracting, with that wall of random shapes (especially after those Mario pics came out). Leno's old cityscape background had this random blob of color that I would be fixed on, trying to figure out what it's supposed to be.