Mainline's products were actually manufactured by Kader in Hong Kong. The owners of Palitoy (General Mills) lost interest in the model railway market. That part of Mainline's tooling which previously belonged to Airfix was aquired by Dapol. Kader continued to produce Mainline's own designs for Replica Railways. Kader eventually decided to market the former Mainline range themselves in the UK under the brandname Bachmann which they aquuired from the USA in 1987. With much improved mechanisms and detailing, Bachmann made a name for itself by concentrating largely on the late-steam/early diesel transition period of British Railways western region, a subject largely negelcted by their main rivals Hornby and Lima. The Bachmann range has since expanded to cover virtually all eras of all regions and is now a very close second in terms of size to Hornby.
That would very much depend on the kind of kit you are looking for.
(kim)