The Minx microdrive looks like a good option to know about. The surface mount and small size are attractive features. A disadvantage appears to be its price - about $56-$60 if my currency conversion is correct. At that price, I could buy three Tortoise switch machines. Although the Tortoises have to be mounted from below but they do have contacts for signals and a well-established record of reliable performance and lasting a very long time.
Hi PGentieu
I am sure the tortoise is a fine machine, I did consider them, however here are some points about the Minx
As per the price you actually get a 2 channel controller and 2 Mini motors, there are 2 relays per channel to operate signals and auxiliaries, for realism the point motor speed is adjustable, I have mine set at mid point
A key issue for me is as the layout is well established getting underneath is a bit of a problem
