For 1/48 scale F-16’s, I still swear by Revell/Monogram. I absolutely love how the upper wing sections are molded right into the fuselage as one part. My only complaint is that the later versions of this kit don’t give the option of an open canopy. Which is probably a good thing considering that I built an earlier version and just couldn’t get the open canopy to look right! There’s nothing really to see in the cockpit anyway unless you use a resin set. You’ll also have to steal some weapons from other kits. Revellogram kits only have one pylon under each wing, but you can still see filled holes (that can easily be drilled out) on the lower wing sections where pylons were intended to be placed.
I tried the Academy F-16 also once and gave up on it because of that wing to fuselage joint. I don’t see how filling and sanding can help that. There’s not enough support under the upper wing, so even if you get the seam filled and sanded nicely, the slightest pressure applied to the wing will crack your putty. I just took the nice weapons load from the Academy kit and stuck 'em on my Revell/Monogram F-16’s.