Both jobs can be boring if you dont really have an interest in
the subject.
Internal auditors look at the control procedures in the company and
reflect to the management internal controls that need to be
improved.
Control checks are performed based on guidelines. Internal auditors
inspect the procedures within the boundaries of the guidelines and
work can be quite routine after some time.
If you prefer to have an overall view of how a company / business
operates rather than get stuck in the meticulous daily accounting
work, choose internal audit.
If you prefer to be where the action is, being an accountant is a
more suitable profession.
Your boss will ask you anything to do with financing. From his
negotiations with the bank, tax issues, financial implications of
certain clauses in business contracts to dealing with suppliers,
customers, government authorities and auditors.
You have to be on the ball all the time and be an
all-rounder.
Speaking from my personal observations,
To be a good internal auditor, your technical knowledge must be
updated all the time.
To be a good accountant, you can actually afford to slack a little
in your technical knowledge if you are good at interacting with
people.
Relationship management is essential in the accounting
profession.
Hope that helps.