Comparison

Sometimes people have studied a similar system before and use this as a benchmark for comparison; rather than the tai chi classics.

Comparison has some potential flaws: the first is you and your ability to correctly interpret what you are seeing.
With tai chi, what you see is not usually what you get - the whole point of the system is to hide the substance.

If you base your comparison on what you were taught; was the tai chi taught correctly and did you understand what you were taught?

As a beginner you will be shown what you need to see and told what you need to hear.
This will not be the full measure of the syllabus.
You are taught in accordance with your ability to learn.