If you want to stay in the centrum and still want to fit your budget, then Ratswaage is the best pick... its a little overpriced considering the size of the rooms and the facilities provided in the rooms. Lack of mini bar, makes you go out to the streets to buy your needs...

Parking garage available but its cost money (cheaper than parking outside the hotel)
Internet - should be purchased via hot spot Telcom
Food - okay

I stayed for two nights in early September.
The location of the hotel is perfect - a quiet location within walking distance of the centre of twon. All amenities are within easy walking distance. The recception, bar and restaurant areas are of a very good standard.
The rooms are large, well furnished and comfortable.
A few small things niggle, but they are enough to make sure that I will not make this hotel my first choice when staying in Magdeburg - and I travel there quite frequently:
1) Internet/WiFi is available in the room, but at €8/hour through TMobile (?) I was not even tempted. I had just come from a hotel in Berlin that was charging a standard €5/day. More and more hotels are offering free WiFi. There was not even free WiFi available in the lobby.
2) There were no international channels on the TV, even though CNN was mentioned on the Channel Listings. For non-German speakers this is a big no-no.
3)No towels were replaced during my stay.
4) The fridge had been removed from the room. There were glasses provided but no drinks - not even a complimentary bottle of water

My impression of the hotel is that some management consultant was brought in to reduce costs, and decided that CNN, clean towels and minibars were costing too much and that they would have to go.

Good food, good service, huge rooms, friendly staff. Located conveniently near to the train station and the pedestrian area.

Good location in the city center. Nice rooms. Friendly staff.
As a business traveller I would, however, not book this hotel again: there is no possibility to access the internet from the room, only a hot spot in the lobby. That is not the standard that I expect at the given price level.
Also, we visited the restaurant in the evening. And the waitress had no clue which dish she was serving.