I was traveling on business and just checked out of the Grand Hyatt. Since it was going to be on my dime, I decided to stay somewhere more affordable. I was pampered and completely spoiled with luxury at the Grand Hyatt...so it's not fair to compare. The staff like any 4 star hotel in Tokyo were warm and accomodating. Everyone smiles and tries to be helpful...I wish all 4 star hotels all over the world share that same enthusiam. The room was a good size for Tokyo, but the bathroom was small in comparison. It didn't have any of the fancy amenities that I experienced at the Grand Hyatt, but hey...it's cheaper. The only positive regarding the location was that the nearest subway station seem to connect with every well known tourist area. All in all, even though it was cheaper, for the price I ended up paying, I expected a bit more.

We were only in Tokyo for a day but got a lot out our time by staying in the New Otani. The staff was very hospitable, the gardens were beautiful as well as the view from our room. We stayed in one of the rooms that had not been renovated and was outdated compared to the rest of the hotel. On the other hand, the Otani is in a great location for restaurants and shopping.

We have stayed in August at the New Otani and it was a wonderful experience. Become a member through the hotel´s website to avoid the long check in lines. Because of this card not only did we avoid the long lines, but also had private check in and upgrade to a just recently renovated room with beautiful decoration, flat screet tv and excellent bath amenities and cosmetics. Customer service and concierge are excellent, but do take the leaflets from their desk as there are activities and attractions not mentioned by them.
This hotel is considered to be one of the top 5 in Japan, but make sure you get a room in the renovated part of the hotel. IT consists of different buildings, more than 35 restaurants, many lounge bars. Be sure to visit the lounge bar on the top floor where you can have a magnificent Tokyo view by night listening to jazz music (reminded me of New York).
The restaurants in the hotel are not the quality you would expect in a hotel of this range but there is a street just accross the hotel with many restaurants, cafes, fast food chains, cigar bar. Also, in the Garden Court (business section of the hotel) there is Tully's coffee (a japanese version of starbucks). There is e number of spas and brand name shops (Armani etc).
One of the most beautiful places of the hotel is the 14th ancient garden with traditional plants, lakes, and buildings.

My wife and I spent Christmas at the New Otani. (We were in Tokyo visiting our son who lives there.
We liked the hotel. It was very full Christmas Eve and Christmas Day. (lots of young Japanese couples seem to treat themselves to a few nights at the Otani over Christmas).
As others have written the hotel is HUGE so avail yourself of the hotel map when you book in.
The food in the main restaurants is way too expensive but used to get a taxi into Roppongi at night ( about a 1000 yen) or get a train ( station 5/10 minute walk away ) to where our son lives in
Kichijoji which had literally 100's of restaurants at reasonable prices.
If you just want a reasonably priced meal at hotel then go to the Aux Bacchanales (go out of Tower exit, turn left and its about a minute away)
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Good lunch for about a 1000 yen.
Also both the main and tower sections of hotel have 3 floors of shops and restaurants ( you have to get escalator or elevator down to the shopping areas.) You can find coffee bar, pizza etc at normal rates.
Just avoid the hotels 'showcase 'restaurants, far too expensive.
We had some drinks in the Bar Capri one night and I ask for some rice crackers. 6 were prented, each in its own wrapper.
I thought it was like most bars where they give you peanuts or whatever to nibble on for free.
I noticed on the bill that the 6 crackers cost 520 yen ,about 40 pence a cracker !
The staff are helpful and friendly, the hotel, the room are spotless, .. but the main reason for staying is the 400 year old garden .. breathtakingly beautiful . Each morning if you have breakfast in the garden court restaurant yoy can look out on to the garden.
There is also a lovely art gallery.
If you intend staying at the New Otani then go on the site and sign up to the New Otani club (its free).
It gives you a few freebies (free entrance to art gallery, no service charge for breakfast etc.) so its worth joining.
To sum up, we loved the hotel and will stay there again, we will not be ordering any rice crackers though !