The one thing I've noticed watching this version and Classic is how much the contestants hem and haw in addition to Alex vamping on that version. I haven't decided which style I prefer though, since Jack's version is fairly dry.
I'm finding it hard to prefer one version over another as well. "Classic" is definitely a looser atmosphere, but the Narz series is more down to business. I did notice (and kind of like) with the 70s shows that when a contestant solves a puzzle, they waste no time in telling them they're right. With "Classic", there's the "Is it (answer)??" from Alex, the brief pause, then the dings/audience cheers/board reveal.
There must have been some sort of offstage signal for Jack indicating the puzzle had been solved, or else he was briefed on it before the show started (which seems less likely). He obviously doesn't have a card showing the answer to the main game puzzles (which would be very easy for contestants to catch a glimpse); I'm kind of surprised he does have them for the Double Play round.
That said, I strongly prefer the car round over Double Play, but I kind of prefer Narz's smooth hosting style over Trebek's.
Jack's hosting has aged better with me than I would have thought. Alex is a lot looser here than on
Jeopardy (and more comfortable than he was on, say,
Battlestars), but there are moments when he tries to get too cute (a couple of days ago he was imitating a female contestant's Southern accent so frequently I wound up shutting it off).
We don't have enough Hugh Downs or Bob Clayton episodes for comparison, but my memory is they were drier than Jack.
You would think I'd have some memory of Ed McMahon hosting NBC's
Concentration, since I absolutely remember Hugh Downs, but I don't. (Granted I was six years old at that point, but still.) Does anybody remember how Ed handled the show?