composite type vs table

Hi,
I'm using composite types within my database and I sometimes need to
modify type either by adding new column or e.g. renaming a column. Of
course I can't do that on existing composite type (actually I can, but
that is quite complicated) so maybe I should use table instead ? With
tables (that are composite types too) I can do many operations, that are
not available for composite type. I would like to ask, whether there are
any disadvantages (e.g. performance) of using tables instead composite
types (comparing only those functionality that is available for
composite types) ?

Regards,
ML