The Maruti Suzuki XL6 would best suit your requirements of mileage and performance. Against the others in your shortlist, the 1.5 litre petrol engine in the XL6 offers decent performance and refinement, but a noticeably better fuel efficiency. The engine has a mild-hybrid setup and, in our standard test cycle, returned a figure of 9.2kpl in the city and 17.0kpl on the highway. We assume, of course, you are comparing petrol versions across the three MPVs in your shortlist, given that the XL6 comes with only a petrol engine. If not, the Kia Carens and Hyundai Alcazar also have diesel engines, and these versions would be more fuel efficient than the petrol XL6.

Unfortunately, there are very few sedan options available today, and between Rs 20 to 30 lakh, you would only find the Honda City Hybrid. The City will meet your requirements of good mileage and low maintenance cost, however this variant isn't really value for money at all. Thus, we would suggest you consider the Hyundai Verna instead. The car may not be as fuel-efficient as the Honda, but it is efficient enough. We put the 1.5 litre turbo petrol auto through our standard test cycle, and it returned 10.76kpl in the city and 16.05kpl on the highway. The Verna is also well equipped and offers good value, and will be reliable and low on maintenance costs. It also secured a 5-star rating in the GNCAP crash tests.

The Mahindra XUV 7XO is a well-rounded product, and the AX7 T is the variant to choose as it offers all the premium features you would expect at this price point. You get a 16-speaker Harman Kardon sound system, ventilated front seats, Level 2 ADAS, an electronic parking brake and much more.As for whether you should opt for AWD, it really depends on your usage. If you live in the hills or regularly drive on challenging and slippery terrain, the AWD version can make sense. For most driving conditions, however, the Front Wheel Drive version will do just fine.If your idea is to get into serious off-roading, the 7XO is not the best choice, even with AWD. For that kind of usage, the Mahindra Scorpio N or the Mahindra Thar Roxx, with higher ground clearance and a low-range gearbox, will be far more capable.

The Tata Sierra is clearly the larger of the two cars and will give you more space than the Maruti Fronx, as well as a better ride, too. However, the base version of the Sierra isn't as well-equipped as the Fronx. More importantly for you, the versions that fit your budget come with the 1.5-litre naturally aspirated engine, which is quite weak in its power delivery and not ideal for you, given that you are mostly driving on highways. Thus, a high variant of the Fronx would suit you better.