Many people have had bad experiences with reliability and performance. Here's a link to several threads with helpful information.
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As the former owner of a CVT car, a 2009 Cube, I was NOT a fan. It seems to be worse when paired with the lower displacement motors (1.6, 1.8, 2.0) but I still think it is awful in the higher ones as well (3.5). I wouldn't own another one. Some of the polite terms I have heard and used to describe them: "Numb. Gutless. No power (especially with the smaller engines). Weird. Awful. No feedback."
Nissan had a TON of problems with them upon first release: overheating, failing, catastrophic failures. They initiated a widespread warranty to cover all expenses associated with them in the earlier model years.
nissan-gives-10-year-cvt-warranty-to-al ... 59873.html Other car companies use them but Nissan seemed to have more trouble than most.
I would tell you to steer clear of them but that pretty much eliminates all of Nissan's current lineup, unfortunately. Nissan claims that the bugs have been worked out and that the newer vehicles don't suffer the same problems as the early models. I would suggest that before buying one, you either take one on the longest test drive the dealer will allow or rent one for the weekend and see for yourself. Some people love them, some don't care, and others wouldn't take one as a gift. It really depends on your personal driving style and what you want out of your car.