The main reason for me to swap the original tuners for the Gotoh Locking tuners is that with locking tuners changing strings is easier and faster.
Please note that the tuning stabilty was not a reason for this change, the original tuners were just fine.
Experience when installing these tuners are:
1) No changes to the headstock was required
2) Screws were on the same spot as originals, so perfect fit
3) The Gotoh bushings, bore 8.8 mm, are smaller than the existing holes, so I used double sides tape to make bushes fit tightly
4) Shaft length is a little shorter than the original tuners, however this created no issues
5) I now have replaced the original bushings (8.8mm) with the right bushings (6.35 mm / 10 mm) which I found at ADP Guitar Parts in France - Gold bushing adaptor for Gotoh SD90/SD91 - Reference TK-0901-002 - Brand All Parts
I am simply a fan of locking tuners, so happy with the change.