The reason they cost is less is because these sound decoders leave out some of the CV's . They are a stripped down version of the real Tsunami decoders . I don't have any ESU decoders , but I would guess that if you compared full featured Soundtraxx decoders to them you may change your opinion of Soundtraxxx . I'd pay extra too for Bachmann to put standard sound decoders into their losos instead of the SoundValue decoders.
