If you're asking for the panel itself, not referring to a specific model, the advantages are follows:
Wider viewing angles
Better color accuracy
Improved black levels
Disadvantage:
Panel has slower response time
I will absolutely say, a cheap IPS monitor can easily get trounced by a quality TN, or VA panel in many ways. While IPS looks light years ahead of TN or VA on paper, you have to take into account the whole package before blanket stating IPS is far superior.