I didn't actually stay at the Lion d'Or, but I did look at some of the rooms available, so wanted to pass on the info I learned.
This place is so cheap . . . the rooms start at only 25 pesos per night (US$9). The rooms at that price are bare-bones -- twin bed, no TV, and no phone. The main reason I didn't stay here is because I needed a phone so local friends could reach me. Next time I go to Buenos Aires, I plan to take my cell phone with me and stay at this hotel. Even with these low prices, the hotel wasn't full and the clerk showed me several rooms. The more expensive rooms (they go up to 45 pesos) have larger beds, phones, and a TV costs 4 pesos extra per day (in any room). There are rooms available in the back that would be quieter.
All in all, I would recommend this hotel to the serious budget traveler. The rooms were clean, but very basic (think Mexico), but certainly acceptable considering the price. If you go there, don't settle for the first room they show you . . . ask to see several rooms since they are all very different from each other. Some of the rooms have updated or completely remodeled bathrooms.