I switched to tiff quite some time ago because it used to have a larger file size limit (4gb) and I kept running into the size limit of a .psd file. I think that changed around CS5 or 6, but no reason to go back.
My number one wish for LR 6 is .psb compatibility because most of my files end up larger than 4gb, so LR can’t access it, which forces me to save a flattened tiff so I can print out of LR.