Ambitions is a fantastic game but unfortunately, a few of the careers are broken due to patches. It doesn't make them unplayable but they become very frustrating and irritating. Thankfully, it's only one or two (the ghost hunter career for one).
Amb does add more to the medical career which is wonderful. Things like vaccination clinics, open clinics, medical courses (that happen inside rabbitholes) and stuff like that. You can also be a stylist, a fireman and (if you love the toddlers) run a daycare centre. It also, as discussed above, allows you to become a self-employed anything you want pretty much! You can be a self-employed gardner if you so desire!!
It also adds stuff like meteor showers and earthquakes (the latter which only happens unfortunately if you are a fireman) which are always nerve-racking and thrilling.
There is also the new furniture and clothing which are beautiful as well as the new town, Twinbrook which is very pretty.
So, I would say it is entirely up to you but I would overall say it is a fantastic game. You can also look at the Sims Wiki where there are great descriptions of every game.
