Totally differnt watches altogether. In my opinion most people today think the 5004 is too small, that aside the complications clearly seperate it from the 3970 & the 5970. The entrigue for me besides being an amazing piece is how few versions of Split Second Perpetual Calendar Chronos have EVER been made by PP. I love the 5970 but am a little miffed as to the sudden rocket in values but I beleive the 5004 will be off the charts in the next 5 years.