The LTD has a Boost and Cache feature not found with the SE. I don't know what the difference is between the boost vs. running in the lower discrimination of the original SE (runs in a high gain setting). I still have an original SE and enjoy it. If you have a choice at the same cost - go with the LTD.
There was also a program of returning the original SEs to have a gasket upgrade for moisture resistance. You might not have that is someone didn't go to the trouble of returning one of the early models.
On some of the boxes for the Regular F75 it says Special Edition but if your F75 has the Gold & Black shaft it is a regular F75. Now, on the Special Edition/Limited Edition the F75 is all black and has a boost and cache mode plus it comes with an extra 5 inch dd coil.