What is the difference between applying for an Employer Sponsered Transition Stream Visa and an Employer Sponsered Direct Steam Visa?

The only real difference is the fact that you would need to apply for a Skills Assessment.
With the transition stream, this would mean that you would have held the Temporary Work Visa for 3 years with that same employer and you will be applying for employer nominated transition stream which provides you with permanent residence.

As a result of working for the employer for 3 years, you are considered to have been skilled along with other requirements that will need to be met. But this does not avoid you from having to apply for a Skills Assessment unless you have an occupation that requires licensing such as Electricians. You would then do the supervision work required during your proposal license to become fully licensed.

If you apply for the Employer Nomination Direct Entry Stream Visa, you must take part in a Skills Assessment. That means prior to your application you must be assessed by the skills assessment authority as having the necessary qualifications and 3 years of work experience post-qualification.
You will be assessed by the relevant skills assessment authority and they will need to provide you with a positive outcome in order to apply.

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