Unless a client chooses a specific brand of machine heads I need to decide what to use, sometimes the decision is based on the aesthetics and sometimes I am just looking for the best tuner at a specific price point. For a long time Sloanes were my standard choice but lately importing them is more expensive and full of hassles so I am trying other things. For now the Rubners seem to be a good choice and the Schellers for the Torres copy. 
These are Ullsperger, probably at least 30 years old and based on the old Reischl. If you are familiar with the Reischl you will know that you have to relieve the wood to make room for the rivets, the rivets on these are twice as deep! 
Gotoh. I bought these to use on a flamenco guitar but ended up using something different, they are not as lightweight as I had hoped.
Faithful Sloane, I have used these for many years. 
Der Jung, new on the scene
Rodgers is always a good choice but pushes the price of the instrument up. 
Scheller is mechanically very nice and I like being able to order them with no engraving.
Here are the Rubners, so far I dislike the screw on the peg, I will have to figure out how to keep it from coming loose.
This is the old Reischl, waiting for someone ask for them on a guitar. These are from my teacher’s estate and they have a fantastic, solid feel.