I don't think many people would swap the CVT for a 6 speed given the 3000 rpm for highway cruising. The beauty of the CVT is that it changes the ration based on load so on a flat road with no wind you might be only turning 2100 or even less whereas the manual is locked into a ratio. This has a big effect on efficiency and noise and comfort.
I drove a Sentra for all of 2km and thought is was a really quiet and refined and well put together car.
No problems recommending it for people to test as a Corolla or Civic alternative.
Cheers,
John M.