Mieca is a thoughtful, responsive host who answered our questions quickly. Overall, we thoroughly enjoyed our stay at Mieca's place, and would definitely stay here again! We only wish we'd been able to stay longer.
The apartment is larger than most other places we stayed while in Japan; it was clean and well-organized, with lots of thoughtful touches. It's also accessible by elevator--no need to lug your bags up to the room, unlike many Tokyo apartments.
The location is also great, in the middle of a hip young neighborhood near Shibuya and Shinjuku. Lots of bars, vintage shops, and cool restaurants are within 5 minutes' walking distance.
Shimo-kitazawa station is very close, about a three-minute walk from the apartment. It's worth noting that this station is not serviced by JR lines, so if you purchased a JR pass, it doesn't apply here; however, you can take the subway to transfer to JR at another station for a few hundred yen.
Since this is a neighborhood with lots of late-night spots, you may occasionally hear people on the streets below late at night. It wasn't a major issue, though; we slept just fine. If you're a light sleeper, you may wish to bring earplugs.
We really enjoyed our stay here; if you're staying in Tokyo and would like a nice apartment near the major tourist destinations (in a charming, fun, slower-paced neighborhood), you can't go wrong with Mieca's place!