The new ones are made from old parts, just with a new barrel, stock, and a few other parts, then they're re-parkerized. You wind up with an M1 Garand with a perfect muzzle and throat. Mine shoots probably better than I can and will give me at least 4 out of 8 shots touching at 100 yards.
I think they're a great buy because gun show and shop M1 Garands are getting almost as much as what the new ones are going for. Plus unless you have a tool to check, theres no way of telling how much muzzle wear or throat erosion there is when you see one for sale. Probably the main thing that attracted me to the newly made ones.
I still may get a been there done that M1 Garand war rifle someday, but untill CMP gets Service Grade ones that guarantee a good muzzle, throat, etc. I'll keep shooting my new one.
Terry Goode got me a great deal on mine from Springfield Armory.