Ranked in these QuestionsQuestion Ranking
Pro A truly distinctive conception of magic
In both flavor and execution, Incarnum is among the most unique concepts seen in D&D. Incarnum users form raw "soul energy" into temporary magic items grafted to their own bodies, providing a variety of benefits and abilities.
Pro Potentially better suited to 5th Ed. than v3.5
One core aspect of Incarnum is binding soulmelds to chakras, which prevents using a normal magic item in the same location. This caused scaling issues in v3.5, but 5th Edition already has a similar mechanic for magic item attunement.
Con Extensive conversion needed
A 5th Edition DM wishing to introduce the concept of Incarnum must provide a full homebrew replacement for its rules. This is unlikely to change.