I use both. I like the on the house deals but I really dislike how EA is trying to shove Origin in order to play the games. Sims 4 was a disappointment for me, but a lot of my frustration was because of my internet problems and the software beinga brick wall between me and the game. Maybe they have fixed that, i haven't played Sims 4 ina good while offline like to notice.
Steam games you can download them and if you open them directly they play. They have sweet deals often and I find cool you can share your screen play and chat while in game with other people. I don't have my own Steam account and instead I just steal my partner's. 