Just a note: the Whyte designation for a Mogul is 2-6-0; that trailing "0" has significance, telling that there are no trailing wheels. But, using the term "Mogul" does pretty much determine that your intent is the designation is a 2-6-0 so your question is understood, but just for completeness, be sure to specify all three wheel positions.
Same for the 4-4-0 (or American), that is 4 leading wheels, 4 Drive wheels and no trailing wheels; if you leave the trailing "0" off you cannot tell if it might be a 0-4-4 (which is a Forney).
BTW: The dashes also have meaning. The "-" indicates a flexible connection and a "+" is a rigid connection: if a loco is listed as a 4-4+2 then the trailing wheels are rigidly attached to the frame, whereas a 4-4-2 the trailing wheels are flexibly connected to the frame.
Just for our European friends, I should point out that they designate the arrangement by axle count, thus a Mogul is a 1-3-0.
I've had great success with the RCS product line. The pre and post sale service are 2nd to None!
Take some time to read through the Battery/RC forums...from there you may get a better understanding of what is avail and what may suit your needs the best. I have an Annie converted (all ele in tender) and an American 4-4-0 awaiting funds to convert (others converted as well, but not tender engines).
A few years ago when I started up, I read and re-read every post on Batt and RC that I could find. I also contacted the different dealers and mfg to ask all kinds of questions...I did my home work...as mentioned above I began with RCS and have no plans to use another control system.
And if you're on a tight budget, the Aristo TE's are quite inexpensive. Since I only use my Bachmann loco at shows and the like, I run it on plain Duracell AA batteries and a TE receiver, all in the tender. If I used it more often, I'd put rechargable batteries in.
"Best" depends on what features you are looking for (or what features you find that you like the best). Check the classifieds here for a new simple low cost R/C system. And don't limit yourself to radio control. There are other options for battery power such as semi-automated (hands on to start and stop, with automated ramp rates and station stops). You can't go wrong with any of the systems mentioned above.