Once you go with Tortoise machines, you will never look back! They mount directly under the switch so usually the only problem is if where you need to put the machine is directly over a support and for that Circuitron makes adaptors and extensions. I installed Tortoise on my last layout built in 1991 and the people who purchased my house kept the layout and to this day, there has not been one failure.
They seem a little intimidatiing to install and wire but once you do one or two, it is really very simple. You can actually control the machine only running one wire from your control panel (assuming you have a ground wire buss run-in under the layout).
Good luck with your decision,
Don
