The Hotel Nikko was horrible. The carpet had lots of stains as well as the bedding. The bathroom smelled like it had just been used. There was rust in the bathtub and mold in the tile. I was traveling with a group of colleagues who had similar experiences. I count myself lucky since my didn't have cockroaches in my room as did two of my colleagues. The service was below average. I will admit that the main restaurant had a decent menu and the food was pretty good. The food aside, stay somewhere else.

The Hotel has two wings. The Non Tower wing boosts of Match Box Sized Rooms and bathroom to match a budget hotel.
At best, can be called a nice Upper class Budget Hotel.
Breakfast is ok, and location is Good.
Has a nice Chinese restaurant.
Nothing more to describe.

I stay in one of the old rooms (we bought the voucher), which has not been renovated yet. The staff told me that the other wing if the hotel has been renovated but not my one.

Ok, the BAD:
The room is SMALL. No kidding about that. I know most Japanese are not huge, but this is international hotel! And the bathroom is even tinier, with sliding door and tiny bathtub, there's barely room to move. The colour scheme of the bathroom is also a bit disturbing (picture old stain yellow). The TV is seriously old and dingy and the remote is hard to operate.
We were using the gym and the pool a lot. And it is a bother to have to go through the lobby area and into different elevator to get to the pool (it's located on different wing - thus the different elevator). But it is just not fun going through lobby with all that people watching you in your bathing suit and towel (and warn you - they do look like they never see people walking through their lobby in their swimsuit)

and the GOOD:
The good point about the hotel is the food. Though it is not cheap, the taste and service makes up for it. The breakfast were good and we try one of the buffet dinner which is superb.
The location itself is fantastic, right in the middle of jakarta where everything is happening. Short stroll away is one of the biggest mall strip in jakarta, but saying that, there is a lot of different hotel available in the area.

So if your looking for a short stay for business purposes, this hotel might not be bad, amidst its location and price. But for leisure traveler, i wouldn't recommend it at all.

When we booked the hotel, we weren't informed of the renovation works, only when checking in, we were told of the works and given 100k rupiah to spend in hotel.
The foyer was the best bit, cool and spacious but you had to order something to enable you to sit on it, otherwise you are pestered by the staff.
We were shocked to see the room. Room was old, carpet was stained, bathroom was so tiny, with sliding door and you have to step up and duck to get in. The remote for TV had a mind of its own.
Breakfast was okay but were told off for arriving 5 minutes before 10.00am and luckily one of the waiters was very kind in offering us coffee refills after their closing time. The 100k rupiah voucher was about enough for 2 glasses of beer. The prices at the hotel is 5 star but the hotel accommodation is more like a two star. We only stayed in jakarta for 2 nights and as we had bought a voucher through local agent it was unrefundable, otherwise we would have moved out after the first night.
It was truly a memorable stay but unpleasant one and would never repeat staying at this hotel again, not even if they pay us.