The Maruti Suzuki Grand Vitara AT will prove to be more efficient, but the gap will not be all that large. Sure, the mild hybrid setup does help, assisting the engine and reducing load. But the bigger benefits come when the engine stop/start is also used. Engine stop/start automatically switches the engine off at long halts and restarts it when you are ready to move, in the interest of saving fuel. 

Trouble is, the AC compressor also goes off with the engine, so on a hot day, you'd rather leave the feature turned off. Do note, engine stop/start is a feature you'd find on the Hyundai Creta IVT too. 

The Grand Vitara should be more reasonable in terms of maintenance and service costs, though. 

Strictly speaking, on product attributes, the Creta IVT is a superior package. It's got a smoother gearbox, better performance and is also roomier than the Grand Vitara. The Creta IVT in base EX(O) trim is pricier than the base Grand Vitara AT Delta, but would still be our pick if you don't mind the stretch.  

 

Since you already own a Maruti Grand VItara, the Victoris won't feel too different, as both these cars are based on the same platform and have a lot in common, including their powertrains. Hence, if you are looking to upgrade, the Tata Sierra is definitely a better choice. Its interior is more spacious with nicer quality of materials used, and ride comfort is outstanding. Also, the turbo-petrol AT configuration is smooth, refined and delivers strong performance.

The best strong hybrid option for your budget right now is the Maruti-Suzuki Victoris. It is a part of having an efficient hybrid powertrain that is well-equipped and easy to drive. 

You could also look at the Victoris’s sibling, the Grand Vitara Hybrid, which is being offered with some discounts now, as a facelift is coming soon. There is no timeframe announced for the implementation of BS7, and there are no BS7 cars available in the market either. 

Getting a BS6 model today won’t make your car obsolete even when BS7 norms come, which is unlikely to be before 2028. 

Broadly speaking, the higher you sit in a car, the more comfortable you are, which is why SUVs and MPVs are more comfortable over long drives. But it's not just the height of the car but lots of other factors like the ‘H-Point’ (the distance between your hip and the floor) under thigh support, the seat cushioning and finally the driving position which impacts comfort on a long drive.
 

Given your requirements, you should consider the Toyota Hyryder, Maruti Suzuki Grand Vitara and Victoris strong hybrid. Since your usage is high, you'll benefit from the exceptional fuel efficiency of the same strong hybrid-petrol powertrain that powers all three. The Hyryder and Grand Vitara mileage is 27.97kpl, while the Victoris mileage is 28.65kpl, which is slightly higher (claimed). 

All three SUVs also come equipped with all the features you want in their respective top-end trims - a panoramic sunroof, ventilated seats, alloy wheels, a touchscreen infotainment system and much more. 

We would recommend you go for the Maruti Victoris since it's the newest of the lot. It has the most features and also a 5-star Bharat NCAP crash safety rating, which the other two don't have. 

As for pricing, the top-spec Victoris ZXI+ (O) string hybrid is priced at Rs 19.99 lakh, while the Grand Vitara Alpha+ (O) costs Rs 19.72 lakh and the Hyryder V is priced at Rs 19.76 lakh (ex-showroom, India).