I've fired the Garand recently. I could see no muzzle flash witht he flash hider but, based on what I've seen from other rifles of similar barrel length in that caliber, not much should be visible. Accuracy is slightly inferior to a full-length M14 but superior to a Yugoslav 8mm Mauser; probably because of the sights rather than any inherent barrel differences. Accuracy was much better with soft points (Remington, better yet with PMP) than with Talon ball. I am still peeved at missing a sale on Greek 30-06 surplus. Soft points are actually practical in clip-loaded rifles because their tips don't hit the front of the magazine on recoil as they do in an AK, for example.
The difference in balance is considerable and favors the shortie. I fired three full-length Garands and (just those three specific examples, two of which were an original US, one was recently built from Italian kit on an old receiver) only the recently built one worked reliably. The other two had problems whereas my chopped rifle did not. Accuracy was fractionally better from the recently built one and similar from the older full-length guns. The advantage of longer Garands may become more pronounced at ranges longer than 25m, though.