The news of this kit is BIG for me. I totally love the 300SL, and the fact that Tamiya will be doing this is like all my Christmases coming at once. I don't think there is any car kit that I have ever wanted this much.
I have several 300SL kits (un built); the AMT one, the Italeri one, the Humborol one, and an Airfix (which is the same as the Italeri) . I have been planning a build for many years, but I will keep these old kits on the shelf in favor of the Tamiya one now.
The AMT kit is the old Frog kit dating back to the late 1960's (as far as I know). It must have been quite an advanced kit for its time, but compared to the Tamiya I think it will be no contest. The AMT is 1/25 scale (so, the wrong scale for all my other Euro cars collection), and has several proportion errors in the body. Knowing Tamiya, theirs will be more accurate.