A bike tour is my preferred tour of Buenos Aires, in fact I bike everywhere in Buenos Aires. It is my preferred way to get around. You will see far more than on a walking tour, and see if far better than from a bus window.

Biking Buenos Aires has great tours, the hardest part is choosing which one to take. I went on their Hidden Graffiti tour of Barracas and La Boca. I highly recommend it if you want to see something off the beaten path, something you wouldn't see without a guide.

If you are short on time, I recommend one of their city tours of the main highlights. You'll learn a lot more from a guide than by walking it on your own.