Apartment rental experiences?

I'm looking to rent an apartment in Tokyo or Kyto for two people for not more than a month, maybe just 3 weeks. I looked around and the most ubiquitous search result seems to be Sakura House.

I would like to know if people have experiences with this provider or know about other providers.

Also, is it even possible to rent an apartment for 3 weeks, for a similar price as one month? It seems to me that once I look for apartments for 3 weeks rather than a full month, the rates skyrocket.

When are you going?
Do you need to stay centrally or say 35mins by train?
How much rental do you consider reasonable for a fully furnished apartment?

Do a search for "weekly mansion."

Sakura House staff, services, properties, etc. are generally okay, it's probably fine for such a short stay. That said, my experience with neighbours hasn't been great. Don't know why but I suppose being probably the most popular agents for new foreigners means they attract all sorts, including lots of people who have clearly never lived away from their parents.

You can stay for three weeks or any length of time you want, but if you move out before the end of the first month you'll still have to pay for a full month (paid upfront when you collect your key) and might possibly lose your (10,000 yen?) deposit.

I have had considerable experience in renting apartments in Japan for short stays, sometimes just for myself when travelling alone, and other times with family or even extended family.
I can honestly say I have had no bad experiences, and all landlords have been approachable people, and often very considerate. However, they set rules, and I believe you must adhere to their requests. Nothing they asked was over the top in my mind. Sorting your rubbish properly was one of their main requests!!
I have had a variety of standards, but all have been very acceptable. Some beds were a little harder than others, but having lived in Japan I know that the traditional bed is considerably harder than the standard Western bed.
Check these places out, there is a wide range of weekly/nightly
costs:
Asahi Homes: These are higher cost but excellent standard.
VRBO Japan: Privately owned apartments in a wide range of locations, and a wide range of prices depending on proximity and size, quality of furnishings.
Tokyoapartments.jp: These are in a range of places and are usually available weekly.
Somerset serviced apartments: Premises in Higashi Azabu and Roppongi.
Hundred Stay Shinjuku Tokyo. This premise used to be owned by a worldwide company called Fraser suites, but changed to Hundred Stay. They were remodernised in about 2007 and are modern with kitchens and bathrooms and sleep 3-5 in most units.
You need to realise in some you pay a bond and a cleaning fee.
Good Luck, it is often an economical way to stay, especially if you can split the costs.

Try liveinasia.com I've used them several times, I always stay at their Nishi-Ogikubo property in Tokyo. They are specifically set up for renting fully furnished apartments to tourists/foreigners.

We have stayed at the Duplex Tower in Ikebukero located very close to the station. Duplex Tower has several locations in Tokyo.
http://duplexcs.jp/eng/