I saw quite a few players mention that they like the embassy. I can see how being in the middle of negotiations can be good in some ways, but it rarely helps you tech up if you have a very targeted tech path (comps just whore techs, they never really go down a path). It seems to me that early on, targeted tech paths are the best way to go. These are the techs I target:
monarchy -> trade -> monotheism -> invention -> leadership
or
monarchy -> monotheism -> trade -> astronomy -> university
The first I would choose for maps where I have limited expansion on my first island.
Second is for when there is massive land to expand to and/or lots of civs to deal with on this large island (crusaders fast are insanely powerful).
Getting back to the point, the embassy seems like it wouldn't really help you techwise, and I don't see any other good merits for it. The chapel, on the other hand, allows you to continue with a nonstop expansion, as you won't need to worry about those pesky red guys showing up from overexpanding. Its especially effective in combo with the gardens. I have a particular deity game where I managed to muster up 5.5million population strung over about 50 cities by 1ad, only possible due to the chapel/garden combo stifling the anger.