Brandon, while I don't have any specific information on the K2a I have heard that quite often the Sunset locomotives will do a little sharper that the minimum advertised radius. I have a Sunset Mohawk and I believe it can handle a 54" R curve and it also a minimum of 56"R. I will check it tomorrow and post the results back here.
As for MTH, I have 8 steam locomotives. One Railking that was converted to 2 rail, one Premier 3 rail, one Premier 3 that was converted to 2 rail and 5 of the scale wheel locomotives. I like the way they run and sound, however I do not currently have a layout so I don't know how well they pull. A long time ago I ran the first 3/2 I ever got on a friends 3 rail layout,it was the CNJ Pacific. If I remember correctly it pulled 16 freight cars which was less than the 3 rail version with a traction tire did. I also ran this locomotive at my former train club. I don't remember it making any clunking sounds going across a switch but I could be mistaken as it was a long time ago.
I agree about the wireless tether. It is not fun to connect and I connect mine the same way Ed does.
i haven't had operational issues except one of the 3/2 locomotives started to stall a lot and it turned out the wheels had gotten dirty. This was when I had a temporary layout which is gone. Once I cleaned the wheels it ran fine again. Now all I can do is back them on and off of my turntable but I haven't had any stalling that I can speak of.
I wish Sunset would put sound decoders in their locomotives as I would be more apt to buy one. Or at least run all the wiring so I don't have to cut the locomotive up to do a DCC install. I have 3 Sunset locomotives and they do make an excellent product
