Hyundai Creta Diesel S(O) Knight MT

The Hyundai Creta King is a good choice. It is a well-rounded SUV that offers a comfortable ride, a spacious cabin, and a refined petrol engine. The IVT (automatic) is smooth and responsive. Being a popular model, you can expect good resale value in the future. 

The Grand Vitara is also a good option, but it is not as spacious as the Creta. Hence, long distance comfort could be hampered.

For you, we think the Kia Seltos would be a better option. The Seltos is a much newer car compared to the Hyundai Creta. Since you intend to sell your car about 8 years from now, the Seltos should be able to get you a better price. 

As for your other queries, yes, you would get used to the dimensions of your car. If you can easily manage the budget for the versions with a 360 deg camera, it's a nice-to-have feature as seeing the immediate surroundings comes in handy in some odd parking situations like placing a car over a pothole, or lining it up against a kerb.

As for ADAS, yes, in Mumbai city traffic, it can often be an issue; thus, it's best to keep it only on highway drives. Coming to the BH plate, it makes sense if you are likely to be transferred and would live in another state, plus you do not have to pay the entire road tax upfront. 

However, you do have to make the effort to pay it every two years online and selling to non-eligible buyers does involve a bit more paperwork. 

The Hyundai Creta IVT is the best pick of the three models on your shortlist. It's got the smoothest gearbox, and engine performance is also significantly better than the Maruti Suzuki Grand Vitara AT and Victoris AT. Fuel economy is decent too, and should not pinch over your 5000-6000km of annual usage.

What also strengthens the Creta's case is that it's more spacious than the Maruti Suzuki models.

However, we'd also recommend checking the Kia Seltos IVT. As you may know, the Seltos and Creta are closely related products. The recently-launched second-gen Seltos is built on the Hyundai Group's latest platform (the Creta continues on the last-gen platform). IIt comes with better tech as well as the promise of better safety. The new Seltos is also roomier than the Creta, making it better suited to family use.   

For the kind of usage you describe, around 178km a day and roughly 46,000km a year - a diesel car makes far more sense than a CNG one.
Firstly, diesel is much more widely available on highways and expressways, which is where you’ll be spending most of your time. With such high daily mileage, convenience matters, and diesel fuel stations are easy to find almost anywhere in the country.

Secondly, diesel engines are better suited to long-distance cruising. Their strong low-end and mid-range torque make overtaking easier and allow the car to cruise at highway speeds with less effort. This also typically results in lower engine stress and more relaxed driving.  It should suit your priorities of smooth cruising, good NVH and long-term durability.

CNG cars, on the other hand, do have a few compromises. Performance is noticeably weaker than petrol versions, because CNG produces less energy. When the car is fully loaded or when you need quick overtakes on the highway, the lack of power becomes quite evident. 

Another practical issue is that the CNG cylinder takes up a large portion of the boot, which can be inconvenient if you are frequently travelling with luggage. From a mechanical perspective, modern factory-fitted CNG engines are much better engineered than earlier conversions. 

However, CNG is a dry gaseous fuel and doesn’t have the lubricating properties of liquid fuels, so over very high mileages, there can be slightly higher wear on valves and valve seats. For someone covering well over 40,000km a year, a diesel powertrain is generally the more robust long-term solution.

Since you haven’t mentioned your exact budget, here are a few strong diesel options across segments. In the compact SUV class, the Hyundai Venue diesel is a good choice with a refined and proven 1.5-litre engine. If you want something larger and more comfortable for long highway drives, the Hyundai Creta diesel remains one of the best all-rounders with excellent refinement and efficiency. 

And if you are looking for something bigger and more premium, the Mahindra XUV7XO diesel offers strong performance, good highway manners and a very robust engine.

Both Hyundai Motor India and Mahindra & Mahindra have well-proven diesel engines that are known to handle high mileage well when properly maintained. Given your driving pattern and ownership horizon of 5 years or more, diesel is clearly the more suitable and practical choice.