I am a big fan of design hotels and have stayed in many of them around the world. Definitely, the Art Hotel is not one of my favorite: too small and impersonal for my taste. Also, the service is not as excellent as I thought (I am a native Spanish speaker and can distinguish between a very nice Argentinian and a not-so-nice one); personal there is polite but does not go the extra mile to help you (also, I have never seen the lady at the cafe' smile). There is one Internet station that, needless to say, gets crowded at "rush hours" (after breakfast, before dinner).
The area - Recoleta - is safe and very residential, but empty and dead in the evening. Next time I would rather stay in Palermo Soho, the hippest neigborhood in Buenos Aires, full of nice restaurants and great shops.
Overall, I enjoyed my stay, but would not return. If you decide to stay there, make sure to avoid ROOM 17, the smalles room I have ever stayed since I stopped backpacking - a two single bed room where you can barely move.
Last but not least, a room for "less than a hundred dollars" is not a steal in a country where prices are extremely low.