I’ve used both the method of loci and repetition plus mnemonic images, but I have only used the method of loci on some. The problem with the method of loci is that it takes a long time for me to create the journeys, so I don’t do it as often anymore.
I also wrote some tips here:
There are a couple of people here who have memorized longer poems of the method of loci, like Dante’s Inferno. Maybe they could answer this question better.