I loved it! Sorry in advance for the long review, but I know that there are some people out there who won't find the neighborhood appealing and I want to make it clear that this is not your typical tourist experience. This is the written in the perspective of an American tourist.
The apartment: It's clean, minimalist, modern, and charming equipped with a washer and drying rack, and a dishwasher and stove. The bed is a futon that is comfortably firm. I never met Junko, but she sent her friend to help me check in and he was very nice and recommended a lot of things to do in the neighborhood. They even left me a bottle of wine.
What you should know about it: It's on the 6th floor of an apartment building and the elevator only goes to the 5th floor, so you have to walk up one flight of spiral stairs. Junko's description is accurate and there is no air conditioning which is pretty typical for Paris. The summers are hot, but tend to cool off at night into the mid 60s (F) to lower 70s. Open the windows at night and use the fan to blow in the cool air. Close the curtains during the day. Like the listing says, there's also no Wifi. I couldn't find a nearby business with open Wifi around either, so download accordingly before you get there. Finally, the shower is a tub with a wand that you'll have to hold and direct. There's no high stand for it.
The neighborhood: Very enjoyable; It's lively with cafes, brasseries, boulangeries, markets, and cavistes all around. It comes alive during the days and especially weekend nights when you head toward Belleville. There are two metro stops close by, one being right across the street.
What you should know about it: The 19th arrondisment is not a typical Parisian movie neighborhood. It's charming, but not in the way that makes you dream of being whisked off to the romanticized past by famous American expats. There are no "major" tourist attractions. Parc des Buttes-Chaumont is close by and Canal St. Martin is a little farther if you're an Amelie Poulain pilgrim. Speaking of which, the closest major tourist attraction is Montmartre which is only a few metro stops away and can be walked if you like a long walk. Finally, there are beggars as you should expect in a major city.
I gave this place 5 stars, because I really enjoyed it. Having been to Paris several times, I've seen just about all the major attractions and wanted a different experience. I'm no expert on the city, but my impression of the neighborhood and the arrondisment is that it consists of Parisians living their everyday lives, set apart from tourism. If you want to observe Parisian life and work on your French while having a charming apartment as your base, book this place.