Even though I am still experimenting with essentially this, I see no real difference when it becomes a fim and I top.

I have learned that sativa genotypes really produce well and stay shorter if topped or Fimmed.......but the colas are smaller. Indica genotypes do better without trimming.

I top mainly for height considerations as I grow about 8-10 different indica and sativa genotypes, and keep a constant cycle going, so I want my canopy in the flower room to be fairly consistent.

Some genotypes will do better, some will do worse with the fim or trim methods