Stayed at the Karlito Apartmenthaus in Berlin over the summer. In brief, spacious, well-located- if you don't mind a little walking, its walking distance from the Hackseher Markt (did I spell that right?), does a fabulous breakfast (not included in the price), very reasonably priced and run by a very pleasant and helpful staff. Its located on a quiet street though, so you're never bothered by any street noise.
To elaborate, we had one of their four person sleeping apartments. Now I travel a lot with these three persons and frankly even in most quadruple rooms, its usually a squeeze, and we're always tripping over each other. Karlito on the other hand, was so spacious that we didn't once have a disagreement over someone getting in someone else's personal space. The furnishings, while not necessarily spectacular, are very nice basic Ikea furnishings, functional, comfortable and did i say it already, spacious. The bathroom is really the piece de resistance. How many "reasonably priced" hotels have you stayed in where there is barely space to stand in the shower, where you can't even hang up your towel and underwear to wear after your shower? Karlito is one of the few where there is plenty of clothes hanging space, so much so, that one can hang up the similar looking hotel towels after a daily shower and know which one is whose the next day. There is a small kitchenette, well equipped enough that we were able to make dinner in the hotel a few nights, having returned from a long day of sightseeing and being too tired to go out. The breakfast, while not included, is extremely reasonable and very generous. In addition, the owner, who's a very pleasant if slightly vague man, runs a cafe downstairs, which can certainly do a drink, coffee or breakfast at a pinch. Be wary of dinner though, as sometimes they can run out if you arrive or return late. His mother, who helps with bookings is also an extremely helpful lady. We had some issues due to which we had to change our bookings a couple of times and also get some documents faxed and so on. This was one of the easiest hotels to get all the information from. So what can be the downside? Well, there is a cemetery diagonally opposite, which to me added to the charm, but I can imagine might be a bit of a consideration for some people. The TV is rather small (which was an issue only because we were trying to watch world cup matches at night), and the toiletries were minimal and of course, there's no fitness center or anything, as its a small probably 12 apartment hotel. Otherwise, honestly, it was truly a great hotel and a great experience.