Olivia is the only PZ coach I can tolerate and its only a small portion of her classes so I mix it in here and there. Generally PZ feels like a day off unless its a max ride, and yes I do update my FTP regularly.

Denis is great. CDE has some great music in her classes.

I enjoy Power Zone classes but they do have a very different feel to them then other classes. You can always take a PZE or two each week and then some of the other classes that you really like. The structure of the PZ classes helps to build the specific area that they are targeting. Matt and Olivia are solid coaches but they are, admittedly, boring. Denis and CDE tend to have better music and are more prone to story telling. Denis is more goofy and fun.

But you cannot deny the improvements you get frm following the program.