I tend to use Phillip Tay for all my repairs because (i) he personally does the work; and (ii) he will be there to answer for his work, good or bad. I know there are mixed reviews about him, but from past dealings I am very satisfied with his work. I call him "Master Tay" and he treats me very very well haha.
I tend to avoid shops who outsource the repair work, because (i) you do not know who actually does the repairs; and (ii) if problems arise, the repairman to whom the work was outsourced may or may not be there to answer for what he did.
I actually have not tried Leica since they started a service centre in Singapore. I always had the impression that if you send your gear to Leica, they will send it back to Solms and you will have a long wait. I think this may have changed now that Leica operations in Singapore have expanded. Maybe some bros can share your experiences here. It will certainly be interesting to know Leica's charges and the scope of their services in Singapore.