This was bought to replace one of the original Nike 'compression' tops from a few years ago, and from my experience the results are just not as good. With the original model, sweat would actually transfer (or 'wick') through the vest and then evaporate, leaving your upper body absolutely bone dry. This latest model however leaves me greasy and hotter.
Comparing both the vests, it appears this new product has a different kind of material and that must be impacting the performance. Obviously I can't vouch for other reviewers, but I'm only comparing this vest to the original release, hence my disappointment. Both are the same size, both were bought from JJB Sports.
For my use it's certainly wearable as an undergarment, but I shall definitely reconsider another purchase in the future.