Acro classes involve a lot of partner work, inversions, concentration. You will work hard but not in the same way to a regular yoga class.  They are very interactive and a great way to meet and have fun with friendly likeminded people.

My yoga classes are taught in a relaxed and informal environment.  

They are physically strong classes and you should expect to work hard and explore your edges. However you should always listen to your body first and if you feel you cannot do anything that is fine.  In this situation I recommend that you take a restful and inwardly focused posture until you are ready to rejoin the class.