Peter, how does PSD give you better results?
The PSD format came about because there wasn't a format that could hold everything that PS could do (alpha channels, smart objects, etc.), however the TIFF spec has since been updated to include all of those things, so I can't think of anything that you can do with a PSD that you can't do with a TIFF now, and the compatibility for TIFF is more universal. That's why Adobe are now recommending TIFF, although it's largely a matter of personal taste.