Italeri's Panther was a highly anticipated release, as Tamiya's effort had so may problems, but the modeling public was hugely disappointed when it finally appeared, as it was riddled with errors. This caused huge aggravation, because all of these errors were completely avoidable. There are several Panther A models preserved in Europe which could have been measured during the kit's development--Italeri just didn't bother, and apparently relied on a poor set of published plans rather than do their own measurements (I have to rely on published plans, too, but I'm trusting the competence of Hilary Louis Doyle and Thomas Jentz, the top researchers in the field).
The Italeri Panther kit isn't so much underscale as misproportioned. If you check the kit against a set of Hilary Louis Doyle's 1/35th scale plans, you'll find the upper hull deck is about eight scale inches short, causing the turret to foul the drivers' hatches when it rotates. Italeri "solves" this by having the turret ride ridiculously high, so it floats over the hatches, when in fact, it ought to clear them. If you correct the turret's sit, it will bang into the hatch covers. There is no simple solution, other than saw the hull apart ahead of the turret ring, and add a styrene extension (or just don't try to rotate the turret with the hatches shut). If you rebuild the hull, the top deck will have to be converted from the interlocked type to the butt-jointed, welded type, as the interlocks will no longer be evenly spaced--both hull types were seen during the A production run.
Other dimensions appear to have been fudged so the kit is correctly scaled when the thick styrene Zimmerit panels are installed.
The gun mantlet places the gun at the centerline, when it should be off center, so out comes the razor saw to cut it apart and swap pieces around so the gun tube is in the right place (or swipe a mantlet from a different kit, or acquire a resin one someplace).
The four rectangular grills on the engine deck have very anemic slats, which are incorrectly spaced, and the four grills do not even match each other! If you have the ancient Tamiya Panther Ausf. A lying around, the grills from that kit can be carved out and installed as replacements, as they are identical in size. If you don't swap them out, the addition of photoetched screens will make the error less obvious, and possibly having some figures stand on the engine deck could solve the problem by hiding it. Forward hull ventilator (under the travel lock) is the wrong shape. Turret ventilator is molded in place with no vent openings, so it must be sawed out and openings added, then reinstalled.
The tail plate is too tall, and must be trimmed to fit the hull. Tools are pretty crude.
Rims on the road wheels are far too prominent (presumably to ease painting), and they should be sanded down a bit. Many kits have wheels with sink marks on the hubs (a chronic problem with Italeri kits generally). If one can inspect the kit parts before purchase, that would be advisable. If you have a friend with Dragon's Panther F or Tamiya's Steel Wheel Panther, you may be able to acquire the spare set of rubber rimmed wheels in those kits.
The kit's vinyl tracks are molded in two runs per side, and are the usual stiff Italeri vinyl. Aftermarket tracks are advisable, as getting these to lay down on the top run of the wheels will be difficult.
But seriously, with excellent A and D versions available from Dragon which include the necessary photoetched parts and single link tracks in the box (and a "not bad" effort from ICM for another version of the D), there is little sense in building Italeri's kit except as a painting exercise. To do a good Panther with this kit will require extensive rebuilding and/or aftermarket purchases, which will negate any real savings.