Those are the only two EP's I have right now. XD
Honestly I use the content from Generations more than I do Ambitions. While I like them both a lot, I have to say that I probably lean more towards Generations. I love all the different family interactions and stuff that game with it, as well as all the new stuff kids and teens can do. :3
Ambitions is also fun, although sometimes I get really tired of the new professions that came with it and always having to follow my Sim around for half of them. It's fun, but gets old sometimes.
Really it boils down to, do you like playing around with family interactions more, or do you prefer to be more job-oriented in your games?