UrbanRegular888
Assignment is cleaner for the buyer because they sit in your shoes with the landlord. A sublease leaves you on the hook if they miss rent. I would not sublease unless the landlord has already refused assignment in writing.
That is the worry. We are asking the landlord for assignment with a release after 12 months of clean rent from the buyer.
Read the recapture clause. Some landlords use an assignment request as a chance to take the space back and re-lease it at a higher rent. Ask for a waiver of recapture in the sale documents.