Over the last year I have cautioned people driving from Sanford to Universal and WDW about the construction on Interste 4 and State Road 408. I drove through there yesterday for the first time in several months. The construction going from Sanford (westbound) is finished to the point where it will no longer slow you down and should not be considered as a factor in choosing your route.
The construction in the other direction (eastbound)still has some work that needs to be done and I do not see that being finished before November or December.
Having said all that, I still recommend that once you get on Interstate 4 from the Sanford airport that you stay in the second to the left lane for as long as you can until you reach your exit.