This is my first Samhongsa brass steam locomotive, and I have to say, I'm quite impressed with it. Yes, it's brass, so naturally it's breathtakingly gorgeous. But beyond all that, it's also a surprisingly impressive performer (particularly for a 1980s model). Pickup is perfect, throttle response is fine at all levels and slow speed creep is excellent. The mechanism itself is elegantly simple and runs smoothly and quietly- no buzzing, no wobbling, no stuttering, no nothin'. Better still, it's also an impressive puller (even without the benefit of traction tires). Mine has no problems hauling nine standard freight cars up and down 2% grades (so figure at least double that on flat track). And from the "gilding the lilly" department, an ala-carte traction tire equipped driver pair is actually provided in the box (should you wish to further upgrade this model's otherwise excellent pulling characteristics).
The pickup scheme on this model is very reminescent of the old Atlas/Rivarossi steamers of the 1960s - IE, one rail is picked up by the drivers and the other rail is picked up by the tender trucks (with current transferred from the tender to the locomotive via a stiff wire on the locomotive drawbar). And although I've had more than my fair share of difficulties with that particular design on other locomotives, it doesn't seem to be a problem here.
I'm not sure how many poles the motor has (it being a closed can job), but whatever the case, it's a quality piece of electronics. A sticker on said motor identifies it as being manufactured in Japan, so there ya go.
On the down side, this model has no lighting (a common deficiency amongst brass locos). Also, the pilot truck is prone to derailing on narrow radius (IE 9.75") curves. And from the "for what it's worth" department, when I first test-ran mine it couldn't navigate 11" curves either. However, after removing the locomotive shell (which requires removing the pilot truck) and then subsequently reassembling it, I no longer had problems with 11" curves. So, a little judicious tinkering with the pilot truck screw might help solve any narrow curve derailing problems you might experience with yours.
The locomotive shell is easily removed from the chassis- simply unscrew the two small screws at the back of the shell (below the cab) along with the aforementioned pilot truck screw. At that point the shell should readily lift off the chassis.
Grade: A (although "F" on narrow radius curves)