This place is gorgeous, perfectly located, and great for groups -- but be ready to climb lots of stairs. The space is large, comfortable, fully furnished with every amenity you can think of (full sets of dishes/cookware, bath products, laundry soap, etc - even some leftover goods in the fridge and pantry).
There is plenty of room for several guests to enjoy their privacy as well as space to enjoy each other's company in the common space. We thought that one person would have to sleep on the couch, but it turns out that the couch pulls out into a double bed -- so it was even more comfortable than we anticipated!
We were happy to take advantage of the washing machine to do laundry mid-way through our trip (and also pleased that laundry soap was provided for us), though it took some time to figure out how a heat-pump dryer works. The rain showers in the bathrooms are amazing. The jacuzzi fits 2 people comfortable but could probably fit 3.
We were able to walk less than a block to take the tram anywhere we needed, and there is a convenience store open late that's right outside the building's front door.
The stairs are a LOT, but as the description says, it's worth the climb - especially if you have a large group. It was tough carrying luggage up and down the stairs or returning after a long day, but I would definitely stay here again, provided that all members of my party were capable of climbing so many stairs. As an American, I had failed to realize that "3rd floor" in Europe is what I would consider "4th floor" (ground level is floor zero, then the first floor up is floor 1, etc), and that high ceilings mean that one flight of stairs might be more than I'd consider one flight of stairs. This is in no way the host's fault, and I was perfectly capable of climbing the stairs (it got easier as the week went on!), but I want to point this out for any future visitors who might find that a problem.
Thank you so much for the wonderful stay! We are already planning a return trip to Prague and hope that we may stay here again.