David:
The Bachmann sets have a 4-6-0 locomotive that is a reasonably accurate, but simplified model of an ET&WNC narrow gauge prototype. It is nominally 1:22.5 scale and is a version of the Big Hauler that is available separately. All Big Hauler locomotives and cars are nominally 1:22.5 scale.
The Spectrum 4-4-0 is a detailed, accurate 1:20.3 scale model of an 1880s Baldwin catalog locomotive that saw service on numerous narrow gauge railroads of the time, and lasted well into the 20th century on many. Bachmann has produced this locomotive in several stunning prototype liveries such as the Eureka & Palisades. All Bachmann Spectrum locomotives and cars are 1:20.3 scale.
Both are good runners, but older versions of the 4-6-0 are less reliable than the most recent Version 5 or Anniversary units. The cheapest sets might have the earlier version (New, Old Stock). Not really bad, but not as reliable as the newer ones.
Bachmann track is made from pressed steel on non-UV resistant ties. The track has very poor life outdoors, but many folks use it for indoor layouts, especially around the christmas tree and similar.
BTW, Bachmann has a lifetime warranty on all locomotives purchased from an authorized dealer.
Happy RRing,
Jerry