At first, let me admit that I don’t own an Omni. My experience is from driving and riding friends’/relatives’ cars.
Strictly speaking, Omni is not really a passenger car. Only in India we call it a passenger cars. I’ve seen Omnis’s in UK roads, but all those are small goods carrier (only driver & co-driver can sit in front). The doors & rear windows are blocked as containers. In Europe, Omni is similar to our 3-wheeled Tempo carrier.
Anyway, in India man is more adjustable than machines so we call Omni a passenger car.
I describe my experience on this car -
Ride - If you are tall and seat on mid/rear seats you will feel uncomfortable for even short journeys. Front seats are though OK for tall people because you’ll get more legroom. The ride in Omni is quite bumpy. Thanks to its light weight, it often jumps on road.
Comfort - I’m yet to seen an AC Omni so far! In fact, because of its small engine and comperatively large size, fitting AC is not recommended in this car.
Driving - I’ve driven Omni at speed of 50 km/h max. in normal city roads. I’ve not driven it on highways. In fact I would never dare to do so. Omni is not a highway car. It’s engine is below front seats. So, you have absolutely no protection in front. Most crash with Omnis proved fatal for front seat occupants. Omni is strictly a city car. However, driving the car is easy. It feels very responsive, pick up is good, gear change is smooth. Visibility is excellent in front.
Fuel economy - Heard that it is very good (~ 12 kmpL)
Maintenance - quite cheap to maintain. Price is also very good.
Practicality - No other car offers such space at this price! The car is really versatile. You can fit an extra row of seat in back (8-seater) or can leave it in its original 5-seat configuration. With 5 people on board, it still has plenty of space in rear. It’s sliding rear door is an excellent concept. Even in Europe only very expensive cars offer sliding doors!
Overall
Omni is definiely a good practical car for city commuting. It’s spacious, cheap to run. It’s only drawback is safety.
It’s definitely not a highway car. Also, recently some Omni’s developed body rust (especially at bottoms). Very early Omnis which were imported from Japan, has high roofs. Later Maruti made the roof flat. In fact, I read somewhere that high roof was designed for stability of the car! Omni has stability problem at high speed. So, no one should drive it fast (> 80 km/h) for safety.
So, I do like the car but I don’t want to own it!