A friend and I booked here for a three night stay, on the basis of an Amsterdam hotels web-site entry, which described it as simple but comfortable, and had an OK photo of a room.
The price was in the budget range (230 euros each for 3 nights), so one wasn't expecting too much, but even so the experience was fairly poor. My friend's bed was under a sloping roof and his room had no curtain; mine had wiring exposed, two areas of missing plaster, bare lightbulbs and a window that would't close properly, which made it very noisy. The rooms were up four exceptionally steep staircases. Although the towel was changed each day, the beds weren't made. Breakfast was served in a cafe next door and was extremely limited.
On the positive side the location couldn't be more central, and the central heating was efficient.
So probably only to be considered if you are willing to rough it a little; certainly I shan't be going back in a hurry

First things first - booked the hostel, then remembered about this website! Had we read the reviews (apart from the owner's obvious contribution at the end!), we would not have booked. As always, is something sounds too good to be true, it probably is - this place is too cheap to be "all that"!
Having said that, it did lower our expectations and the place wasn't AS bad as we were expecting.
Amazing location - quite honestly couldn't really be better. Half way between Centraal Station and Dam Square....but that's about the only good thing.
Lots of steep stairs - impossible for wheelchair users (not that there were any in our party), but not ideal when one is a little worse for wear, as is so often the case in Amsterdam!
Room for 5 of us was relatively small, makes you want to go out and see what there is all the more!
Seriously uncomfortable beds, palpable springs and questionable mattress stains, at all angles!
As another reviewer mentioned, the carpet is also questionable...
...and the piece de resistance, the MASSIVE gaping hole in the ceiling (see photo!), which was also mentioned in another review, which leaked...and leaked...and leaked! It was raining most of the time and we think that may have had something to do with it but we were on floor 3 of at least 5 or 6 so it doesn't quite add up. The manager/receptionist wasn't too bothered and just gave us a waste bin to put under the incessant leak (see 2nd photo!).
The bathroom was adequate, and was at least clean - there was a panel in the shower door missing, i.e. half a door, and this made showering a little difficult trying not to flood the place if the shower was angled incorrectly. There were also couple of ceiling tiles that would have caused some serious harm had they fallen on someone. There WAS a soap dispenser in the shower though, which is always a good thing if you are the kind of person that always forgets shower gel!
I didn't experience the breakfast room myself, but obviously some strange Dutch (or other national) traditional breakfast is bread and sugar in a room that (from what I could gather) was just a room they weren't sure what to do with.
The place was relatively clean, considering, and I think I've stayed in worse, but would not stay there again. We got a refund for 1 night (out of 2), which we supposed sweetened the pill a little, but the management's indifferent acceptance of our dissatisfaction makes you wonder why they don't do anything about it. The place needs gutting and renovating pdq - I doubt they have many returning guests.
All in all, if you REALLY don't care, this would be the place for you, but if you have high cleanliness standards, service expectations, hunger in the mornings, an insistence on intact facilities or a disability, I don't think this place is for you!
Still, this is Amsterdam, and if you sample enough of the local delicacies, you may not even care!
Enjoy!! (and remember to add your review for wherever you stay, viva Tripadvisor)

Staff - On arrival the gentleman on the desk carried our cases up the 4 flights of stairs to room 25 which was very kind and thoughtful, on departure a different guy said he would offer to help but had a "bad back", aye right!
Stairs - steep, narrow & dirty.
Room - Damp smell, suspect linen/towels, I refused to walk on the carpet, had I been able to levitate I would have done so over the bed rather than lie on it. On the last day a 6 legged creature had me screeching in the bathroom, I wouldn't tell my friends what it was until we were at the airport.
Breakfast room - small, functional, fine. Bread, meat, cheese, preserves, tea, coffee and orange juice.
Location - amazing, really central, hence the name!

On the whole the hotel could do with a really really really really good clean and needs redecorated pronto. We gritted our teeth, got on with it and had a great time, only returning to the hotel to change and sleep. But if you were a family or senior citizen or have a phisical disability then this place would be, er, a challenge.

As we booked the Center Hotel over the internet, we were unprepared for what awaited us. The steep stairs to the first floor reception area were dirty and the tiny reception area had ceiling tiles missing, with electric cables hanging through the gaps. The manager insisted we pay for all 4 nights we had booked up front. When we saw our room, which was up another precipitous flight of stairs, we could understand why. When we entered, the room smelt strongly of damp. The room was tiny and there was barely room to walk around the beds. One of the beds seemed about to collapse, as when one sat down on it, the side of the bed touched the floor. The walls and curtains were filthy. The "bathroom" was a tiny cubicle without ventilation and there was a towel stuffed into a gap between ceiling tiles, presumably to stop something leaking from the floor above. There was no plug in the washbasin, and when I approached the manager about this, he told us that a plug wasn't necessary and that we should just keep the taps running and splash our faces. The TV was held on to the wall bracket with a knotted strap. The tiny wardrobe contained 2 hangers, 1 shelf and 2 dirty pillows. There was no other storage space. The room in which breakfast was served was about 3 metres by 3 metres, with a narrow chipboard shelf running around the walls, 2 small tables and about 6 upright chairs with filthy covers. As we didn't arrive until 8.30pm, we stayed there for 1 night and found an alternative for the rest of our stay. The manager did not seem surprised at our expressions of dissatisfaction and readily agreed to refund our money - which, somewhat to our surprise, he did.