lookup verus dropdown anything to consider

Hi

Am building my forms in zoho and i tend to keep using lookup instead of dropdown

Good Reasons for lookup so far are
1) With a lookup, one change is reflected in any form that uses that field
2) I can have columns in a lookup which with the advanced display helps a lot
3) I can list alphabetically
4) I can select a default
5) The default entry to the user is -select- stops me from thinking about it

so far all good...

question, am i missing something which is going to trip me up
or another way
any advice or experience on when to use lookup or dropdown