In terms of power, the Ritz is obviously better as the engine is bigger. Beat is the most efficient car in the country today, especially under city conditions. Ritz is also pretty efficient in its own right, but not as much as the Beat. The Beat's engine is essentially the same as the Ritz's, with one cylinder less. So the Beat looses out a bit in terms of performance and the Ritz gives accordingly lower FE. Suspension setup of the Beat is excellent. The ride is very comfortable and silent. Engine noise and vibrations are lower on the Beat as well. Both Ritz ZDi and Beat LT(O) come with a similar feature set. Beat does not have steering audio controls, but gets the automatic climate control which is absent on the Ritz.

Mileage is the only factor where Beat wins over Ritz

If your usage is primarily in the city and / or the cost of ownership is of importance, it is definitely the Beat with a maintenance package as well as a noticeably fuel efficient engine. If your usage would require a stronger engine and the budget allows for a higher cost of ownership, the Ritz is the car to put your money on.

NVH levels are also influenced by the quality of the engine lining, hood lining, various rubber mounts, door beading, matting, many other plastic and rubber components which are placed to bring down the NVH levels apart from the engine configuration. Unfortunately Maruti's cost cutting efforts show very heavily here. My diesel Punto makes huge noise every morning when I leave for office. Its typically cold and the ambient temperature is less than 20 degrees and its the first start of the day, it sounds very similar to a small Tata truck on the outside when I pull out the car and shut the main gate while the engine is running. But the moment I sit inside and start driving, it feels more or less like a petrol Maruti, that is the beauty of quality plastics and rubber, very low NVH for the occupants. Once the optimum running temperature is hit, it gets noticeably quieter even on the outside for any diesel engine. The Liva uses a 4 pot engine and is the most horrible diesel hatch from the NVH perspective. The Figo (4 cylinder) and Beat (3 cylinder) are definitely better than the Ritz, the Polo and Fabia are better than only the Liva. NVH is an outcome of a lot of variables. Regards.

@Ashu. I suggest you TD both cars. Chevy has done a fantastic job with the insulation and balancing of this 3 cylinder diesel engine. It is surprisingly smooth, refined and vibration free. Certainly quieter than the 1.3MJD/DDiS.