Personally I really enjoy 'Get to work". I do like the fact that I can experience their workdays. I admit I only have this pack recently, and I started a game with one sim, so she gets all the attention.
Perhaps there would surely be a problem when you try to combine two or more sims with an 'active' career, you would have to choose the one you share the workdays with.
It is something different, but definitely worth to experience, from my point of view that is.