We here at Quality Floors Direct get asked all the time which we prefer.  Our simple answer is this.  We (that is our installation team) cannot duplicate or warrantee the finish on a traditional sand and finish floor the way a factory finish can.  A sand and finish floor is beautiful, but  a pre-finished floor is easier for a homeowner.  When you are installing a pre-finished floor, there is less of a hassle to the homeowner. There is not any worrying about not being able to use that room or walk on that floor for days at a time.
    A commonly asked question is “Can we refinish a pre-finished floor.”  The answer to that is yes in most cases.  A solid ¾”  pre-finished floor may be refinished.  We have had many instances of customers calling us to refinish their pre-finished floor and they have heard mixed answers.  Well, we have refinished many pre-finished floors without a problem.
   So either way you elect to go is up to you the customer, basically it comes down to you the consumer deciding what is best for you.