If you want the best location possible then stop looking and book this place, NOW.
This place is within walking distance of everything, 30min to the castle, 45min to Vysehrad and everything in between. We did the Taste of Prague food tour and found out that Zuzana's place was within a block of 3 amazing restaurants (Lokal, Nase Maso and La Bottega) and then 3 blocks from one of the best cocktail bars my wife and I have ever been too (Banker's Bar).
The place itself is perfect for anyone looking for a simple, clean and minimalist place to stay. It doesn't have all the amenities that a hotel would offer but it has the essentials. If we were ever to travel back to Prague again, this would be our first pick!