Welcome to the forum.
They're both great guns. What is this for? Carry? HD? Range?
The XD45 shoots extremely well, but bulky for carry IMO. I switched away from XDs because I personally like the Glock trigger more, but everyone is different. Shoot them all if you can before buying. I used to carry an XD9SC, but now carry a G36 (single-stack 45).
Good luck with your search.