People like to rag on CVTs but I've driven a Maxima with this drivetrain and I was happily surprised at just how good it was. I'm sure it's fine in the JX too.
I've driven the Maxima too - it was high on the intended purchase list to replace my '07 Altima. It wasn't horrible by any stretch, and for the most part the CVT was pretty much "okay". But I sure wouldn't choose the CVT over a DSG or a good 6 speed automatic. Ultimately the CVT was a deal breaker - not because it was terrible, but because for my purchase dollars the drivetrain has to be better than just passably okay. I have to actually like it.
I think the more sporting the vehicle's intention (or pretention) the less appealing I find the choice of a CVT. It might be I'd find it less off-putting in something like this JX versus the Maxima. But I still suspect my dollars would end up going to something with a conventional auto and a bit more power.
Jaeger
I completely agree with the assessment re: Maxima & CVT - if Nissan is going to market that vehicle as the "4DSC" (flagrant false advertising IMO when no M/T is offered!), then the CVT - good as it is - is not the right transmission. It doesn't make the Maxima a bad car at all, but other than the styling and a few features, why is it any better than a V6 Altima? It certainly isn't "sportier", even with 19" wheels and a different suspension tune.
Now for the JX, I can't see how the CVT will cost Infiniti any sales. It certainly hasn't cost the Murano any. Could it be a problem for the upcoming Pathfinder, with its proud off-road history? Maybe, but not for Infiniti's family luxo-barge.
I'd like to see a comparison of a top-of-line Quest against the base Infiniti JX. Both would come in about the same price (~ 45K before tax). Both are skewed towards the luxury/touring side of the driving spectrum. Infiniti has AWD, Quest probably has more features at that price, and likely a little more space (though not as much as other minivans). But I'm guessing Infinit will sell FAR more JXs than Nissan does Quests.