I have two issues with custom fields:
1) In the old system, all of the custom fields I used were in one screen where I could update them easily and THEN save. Now I have to update one by one. Much more time consuming with I just need to update 2-3 people.
2) Also, in the old system, my most commonly used responses were available in drop down boxes. This option is no longer available and more time consuming when only updated 2-3 people.