Here are some reviews of the place, by people across a couple of websites and information groups.
1. I have stayed in the Garden City House Hotel multiple times. It is a favorite place for archaeologists passing through Cairo on their way to sites. I think it is a favorite because of it's location -- close to the American Research Center in Egypt office (across the street) and the Egyptian Museum -- and because it traditionally was a good value. However, I have to say that I think 100 LE per night for a single room is over priced for what you get. The staff are nice and it's a very good location, but its nickname among people I know who've stayed there is the "Garden Shitty".
Sometimes you luck out and get a decent room, but sometimes you get one where the a/c or toilet isn't working (they'll repair it, but not necessarily the same day) and/or where the bed sags and the pillow is rock hard. Also, I don't think they've painted the walls in the building in a few decades -- the massive amount of dirt smudges is really unappealing. Don't get me wrong, I have many fond memories of my stays in this hotel, but that is partly because of the comedy that sometimes ensues from the state of the accommodations and the other people staying in the hotel with me.
That being said, I'm not sure you have much in the way of other budget options for that particular area of town. From what I've read, there are good budget places elsewhere, but none as close to the Egyptian Museum (if that is important to you). I'd suggest looking in the Lonely Planet guidebook if you want other budget suggestions. I've always stayed at the Garden Shitty because someone else was paying and choosing the place.
Another option, if you really want to be close to Tahrir Square and/or Garden City is the residence in the American Research Center in Egypt offices. I tend to think they are a little over priced too at 25 USD per night, but you get a lot more, especially if you'd like a place where you can make your own food. It's more like a shared apartment -- a few bedrooms, one bathroom, and one kitchen. But most of the time it is not full and you may be the only one staying in one of the rooms. The only catch is that you must be a member of ARCE to reserve a room, but this is not too expensive if you are a student. You can check them out at www.arce.org
2. Garden City House is basically a hostel, similar to other hostels around Tahrir such as Ismailiya House, and New Sun Hotel (over-priced for the rooms you get). This is convenient if you are working near Tahrir, Garden City, or even other areas such as Zamalek or Doqqi.
3. Zora : Garden City House: I've stayed there, and I found it to be dingy as described, but actually a lot more homey than some other, cleaner budget places. My bathroom was enormous and I had a full tub and a dedicated hot-water heater. I didn't use my a/c, so I'm not sure whether it worked or not.
I really appreciated the fact that the staff, while very nice and polite, did not want to get into my business at all--I could come and go as I pleased (I was staying there alone) and didn't get a single question. (More hostel-y places with younger staff can just be a daily battle with getting hit on.) The location in Garden City is nice too because you're not descended upon by touts the instant you step outside. The traffic noise is pretty severe, but I guess that's everywhere but Zamalek.
I also really, really liked Pension Roma. Equally homey feeling but much better kept, and very used to people staying for weeks at a time.
The only drawback is that there are no rooms with en-suite toilets (some have showers, though), so that can be a deal breaker for some people. Also no a/c, but super high ceilings. There's no online booking or email contact--just reserve by phone, but that's worth the effort (whoever answers will speak perfectly good English).
By the way, I wrote the Cairo chapter of the Lonely Planet Egypt that's coming out in May. I generally agreed with the recommendations in the previous edition (8th), but they tend to favor the chatty backpackers' places over the mellower places with less of a social scene (and Pension Roma does not rank high for this reason, I guess).
4. I stayed there for like 3 or 4 days when I first arrived in Egypt. It is a good location but you can DEFINITELY do better. It sucks. The showers are awful and the beds are the worst. Look into other hostels, they are all pretty much the same price. My friend stayed in the King Tut hostel and he said it was good. Don't stay at the Garden City- its awful.
5. Vivian : I agree with the previous post. The Garden City is simply dreadful especially arriving at 4am from Europe. ARCE has beds on site. But the Nile Zamalek Hotel is a great alternative and a 5LE taxi ride to Tahrir and ARCE.