I co-developed a study that focuses on the long-term reliability of engines and transmissions. We now have over 1.8 million vehicles that have been inspected by professional mechanics.
Overall we have found CVTs to be a mixed bag. For the most part they are not nearly as reliable as conventional automatics for two reasons. First, the maintenance schedules on these units are either too long (Nissan and Chrysler in particular) or non-existent. If you want a CVT to last 200,000 miles you will have to get the fluid changed regardless of what the OEM is stating in the owner's manual. Preferably, it's best to do this somewhere between the 30k to 50k point.
The second issue is that these units are engineered for vehicles that have too much power and weight to handle the capabilities of that CVT. Every minivan and SUV that has a CVT is ranked far below average when it comes to long-term reliability.
A light vehicle that is a compact or smaller will generally do better than most other alternatives if you must have a CVT for whatever reason. Also, there are some units in the marketplace that are technically not CVTs such as the ones used on Toyota's Prius line.
Hope this helps!
Steven Lang
http://www.dashboard-light.com/