We stayed here once in November of last year, and then again this year in July.
Take note: They recently relocated and it's no longer as ideally located as it previously was.
We didn't know this on our second stay and directed our driver to their old location only to find that they had moved. So we pretty much got ripped off by the taxi driver who took advantage of the fact that we didn't know where we were going and drove us around on a huge detour for which he charged 3500 shillings.
The new location is absolutely gorgeous, especially if you arrive at night as the pond is surrounded by lanterns and the terrace overlooking it is lovely. So the atmosphere gets five stars from me.
If you are planning to go into Nairobi during the day, the taxi will cost you a fair amount. We took matatus and local buses, so it was quite cheap, but it can be difficult to get back that way unless you know your way around.
We stayed at one of the "budget rooms" which unfortunately, at 3500 shillings, are no longer very cheap. Last year they were 2500, which was more reasonable, considering that all you get is a very small room with shared bathrooms. The rooms are very basic, and the curtains were hanging by clothes pegs, which I thought was a bit ridiculous considering the price we were paying.
Anyway, I don't think they are really geared towards budget travelers anymore, as they have many more luxury tents and only three budget rooms. (Although you can also pitch a tent, but the price for that is, in my opinion also a bit high)
If you have money to spend, you'll love it here. The owner is great, and his kids + dogs are adorable. But you will be charged quite a bit for every extra thing, from extra showers to towels to internet, and I wouldn't recommend it for budget travelers.