I spent ten days at the Marriott during a business trip to India in January 2012. The hotel was an excellent retreat from the hectic traffic and pace of the city. Here's what I liked the most:

1. Great staff. I found all staff to be very, very helpful, engaged, willing, and professional. From front desk to waiters to room service, they were all great.

2. Comfortable room. The bed was large, well appointed with numerous pillows, and very comfortable. I slept very well! It took me a little while to figure out the air conditioner controls but, for the most part, the room temperature was fine. The room had a sitting area (with a couch and table), a work area (with internet connection), and a spacious bathroom. My only issue was that the wardrobe was quite small (see my photos).

3. Internet access. The hotel has two types of internet access. Executive rooms and lounge have wireless access. All other rooms have access via an in-room cable. Access is free to Marriott Rewards members. I was able to connect very easily and the speed was high enough for me to watch videos and make international Skype calls.

4. Food. The hotel has a very good main restaurant that offers both a buffet and food from the menu. The focus is Indian, of course, but there are Chinese and Western items. Overall I found the quality and range to be very good. The chefs and staff were very helpful - they navigated me through some new Indian dishes. There's also a very fine Italian restaurant that serves very good food. My only issue with it was the dreadful "rap" music, played at a high volume. Totally inappropriate for what was a quiet and supposedly romantic spot.

I really enjoyed my stay in the hotel and would recommend it to business and other travelers.

Excellent staff; good rooms. Overall, this is a good hotel. The staff go out of their way to ensure that all aspects of your stay are well-taken care of. The rooms are nice but all rooms face abandoned neighbouring buildings. The two restaurant choices are fine. The breakfast buffet is amazing. Go earlier to the main restaurant if you want to avoid louder music because the bar adjoins the restaurant. Close to several shopping destinations.

I was travelling on work and was just staying for a night. The room was decent and comfortable. But the in-room dining food was most ordinary. Salad and dressing was brought separately for me to toss, without appropriate tossing equipment. The breakfast had cold eggs, randomly cut ham, no toast (despite request), and no coffee. The coffee cam much much later.

While there are better looking properties in Chennai, what sets the Courtyard by Mariott apart from all these is the overall experience which leaves a lasting memory.
Right from the time you enter into the hotel - the security staff, the reception staff are all out there to make your check in comfortable. The hotel outlay is quite standard and the rooms are spic n span and very very comfortable. The linen and towels quality is outstanding and due care is taken to ensure that they are very soft, clean and sparkling white. The wash basin, mirrors and the bath area are awesome and one literally gets a ''wow'' feeling. The kings bed was very comfortable. What stands out is the fact that due care is taken to ensure that every single item in the room is properly identified and improvised to ensure that there are no complaints.
The best part of the hotel is the food. The chef Satish (I specially asked for him) ensures that the spread of the buffet - whether breakfast or dinner is meticulously planned and none of the items were repeated during my 3 day stay at the hotel. Best part of the menu was the pizza which was on the house with the buffet and I did not expect such tasty and unique Italian, Chinese, Indian and South Indian spread on the menu.
The best part of the breakfast was the kaapi (filter coffee) that was served in traditional road-side Chennai style in a glass and a davara (a small cup on which the glass is placed). It is quite surprising that the staff even at the restaurant remember your names and tastes. For example the steward remembered my preference and exactly asked for it the next day.
Two aspects which the hotel could improve upon is the TV channels - they do not have CNBC TV 18 one channel that every business traveler would like to see. There is a very limited choice. The other is that the view of the hotel from the rooms within are not good, but this is due to the very design of the place. But who wants to stay in a room, when you have an excellent gym, heated jacuzzy and a great steam room for rejuvenation.
This is one of the best experience that I have ever had with respect to service in any hotel ever.