Hello,
Here are my experiences, after I have recently dealt more intensively with the LTMC and the LTMOM.
The LTMC is a good alternative to the LSMW, especially for those users who have never dealt with the LSMW. BUT the structure or arrangement of the columns in the templates does not correspond to the arrangement of the columns in an unprocessed download from an ECC system. I.e. either each column must be copied and pasted individually, which is of course very error-prone, or you "tinker" a Quick Viewer, in which the corresponding columns are sorted correctly. Adjusting the template via LTMOM is also possible, but here only one column can be moved in the order at a time, which is very time consuming. If someone has a better idea, I am open for everything...........

Another point is that there are simply missing fields that exist in the SAP system, but not in the template, and these must then be added. Is in the LTMOM also not quite so difficult, in the material master, however, that was with us more than 90 (!) Fields, so also very time-consuming.
Furthermore I miss the migration object for the business partner. Customers and vendors are created with the general role Business Partner, but if I have already done a Customer-Vendor-Integration in the legacy system, there is no separate object for this. Would be happy if someone who has already had experience here shares it with me.
Best regards
Tilli