I bought get to work during the sale, I'm having fun with it. Discover university it is meh to me, I feel like it is a add on pack for Get to Work because you essentially send your sims to school for what? to get them a head start on careers. and you wait for them until they are done with class... there is no game play in that. There are organizations which my sim, she didn't have time to participate because she was busy doing homework and finishing her finals. The grading system is also weird I had notifications saying my sim is doing great in class she did the final projects but ended up with a D+ or a C.
That was my experience with DU, why have your sim go to school when you can have them get into a career instantly. With Get to Work there is gameplay with the 3 active careers where you see your sim get to work, unlike in Discover University where you just discover university...
I say go for Get to Work. :)