I dont have any experience with the troller handhelds . DC units really fall into one of three categories ,resistor , transistor , Integrated.
Resistor throttles were the first and were used in train sets up till the seventies , speed regulation was poor engines would start to move and then stall , to get something moving you had to raise the voltage and then throttle back any change in load due to curves, grade ,ect would cause stalling.
Transistor throttles started showing up in the 70's , advantages were constant current thru the motor which results in constant torque on the motor giving better speed regulation , stall on grades and curves is mitigated .
Integrate throttles start showing up in the 80's ( I had MRC Tech II ) , more or less constant voltage output resulting in constant RPM on the motor , stalling with decent quality motors was reduced and with better quality motors almost eliminated entirely , A Tech II I could put a Athearn F w/ Holland and ten cars , point it at a 2% grade , start it on level track at around 5-7 mph , and when it hit the grade it would make it up with only a slight decrease in speed. You couldn't do that with a cab 55 on the same run, you'd have to get up to 15 even with that big Holland, but it was still better than resistor pack .
All the MRC Tech throttles are integrated , unfortunately back in the 80's MRC didn't make a walkaround with memory , so I ended up making my own .
