Depends on what other functions you want your machines to do; ie. control panel lights, control signals, assist in non-derailing, etc. I used the NJI twin coil machines when i started building the Not-So-Great Eastern in the late 1980's. If i could have afforded it back then i would have used Tortoise slow motion machines. Unfortunately my wiring which includes two push buttons and two LEDs on the panel for each of over 30 turnouts makes changing over without a complete re-wire impossible. The NJI machines are of dubious quality as they are copies of the old Tenshodo twin coil machines (but with the quality going away before the name went on). Whenever i find the old Tenshodo machines at train shows i replace the NJI units. Most of my turnouts are the older GG type with a few Ross and Curtis units mixed in. If i could do it over Tortoise would be my choice.
Jackson, CEO - the Not-Great-Eastern R.R. aka the Never Done Lines
Division of the Southern Adirondack Railway Cartel
http://www.youtube.com/watch?v...&feature=channel