I agree about motion not being a requirement for a useful training device. However, the new regulations we are setting out through the IWG (RAeS) are likely several years off, so if you want checking credits now you're pretty much forced into going with a full flight sim over an FTD... and that requires motion.
If you just need training credits, then an FTD is the way to go.
If you want both training and checking credits, an FTD3/LevelB device is the most cost effective.