We stayed in a 3 bedroom apartment for almost 2 months with our 2 small children when we first moved to Kigali and were looking for a house to rent long-term.
The apartments are good-sized with a large dining/living room, decent sized kitchen, good sized bedrooms with working mosquito nets installed, a small office, and 2 bathrooms (1 en-suite in the master and a second off the hall separated into a room with a bath and a second with a sink/toilet). The kitchen is workable but not very well stocked for real cooking with only a few basic pots and very few cooking utensils. There is a full sized fridge with a top freezer which worked well and a typical for the area propane stove, also a toaster and a microwave. There is no where at all to do laundry yourself and prices for their laundry service are 5 star hotel high which seems unacceptable for an extended stay place. If you hand-wash your laundry (which is what we ended up doing because there aren't really laundromats in Kigali and we weren't paying $100+ USD to do our laundry each week) there is no where to hang it either - no clothes lines even in the bathroom or on the multiple porches so we ended up hanging it on the porch railings when it was dry or around the apartment when it was wet which didn't work so well.
The beds were decent - the pillows weren't but since we had come to stay we had traveled with our own pillows anyway.
The water pressure was mostly adequate and mostly reliable (only a few days in our 2 months without water) and the electricity relatively reliable for Kigali (it generally goes off for a brief period of time at least once a day but is the fault of the city not the hotel). There are no shower curtains on the showers (also fairly typical of Kigali) and in one of the two apartments (we moved out and back in at one point during our housing search) the shower head had a wall mount, in the other it didn't so you just have to hold it (also not unusual for Kigali). In one of our apartments the towel rack was broken off and the sharp metal pieces were still sticking out from the wall - I whacked my head on one once and almost cut my head.
The bathrooms were relatively clean without too much mildew. They do come in and clean every day. The cleaning staff speaks almost no English and little French (mostly just Kinyarwanda) so communicating with them is difficult but they were always very sweet. The mop the floors but they don't sweep ahead of time so they mostly just spread the dirt around so my kids had permanently black knees and socks and filthy hands from playing on the floor. Remember that the cleaning staff are only making $50 USD per month so I could never judge them all that harshly.
The office staff were very nice and helpful. They even called us when we accidentally left a bunch of charge cords and documents in the room when we moved out.
The location is convenient to the U.S. embassy but you pretty much need a car or to brave the buses to get anywhere else. It is right next to the Umubano (Novotel) which is a relatively fancy hotel with a pool and fitness center you can pay to use and a very over-priced restaurant and decent bakery. There are a couple of small corner grocery stores and a bad pizza place nearby as well.
We always felt safe here.
This place is moderately overpriced for what it is and what prices for other rentals are so if you are staying long-term not the best but for short-term when you don't yet have a feel for the city and what else is out there it certainly fills a niche and is better than a hotel room with a family and you can at least do basic cooking. They do have nice grounds with paths and trees/flowers/lawns that the kids enjoyed. You can get a monthly rather than nightly rate so if you'll be there for a while don't forget to ask for the long-term rate.