I've stayed in Oleg & Miriam's apartment for one week in October'2017, and must say that it is one of the most brilliant places in Prague I've stayed in (and, believe me, I've visited this city a lot of times :) ). Equipped better than most 4**** hotel rooms, it leaves little to wish for. 5 minutes to metro, then ~12 minutes to city center; super clean; huge selection of coffee and tea; supermarket, pub and several restaurants nearby. I want to especially note a stable and super speedy Wi-Fi - thanks for that!
Also - not a complaint, but a word of warning for non-EU travellers: proprietor of this apartment *does not* do the registration in local foreigner police for you, you'll have to do it yourself; be sure to google that before you visit Prague.