Next year (starting from January 1st) I am planing to work for company "A" as self-employer (software developer/consulting) for 3 month. After that I am planing to work as full time employee (W2) for the rest of the year for company "B".

Does it make sense to open LLC or S-corp for 3 month self-employer job or just go with Schedule C (Profit or Loss from Business) in individual tax income 1040?

What is the benefits and downsides of opening LLC or S-corp in this case?