My family owns an Alto for the last 7 years. The car is highly reliable, excellent AC, great ground clearance, cheap upkeep including fuel, decent resale, etc. Ours has 170K km on the clock and still going strong.
The negatives are poor brakes, horrible pick, overall poor driving experience. If you are driving on motorway, just mind your own business, dont think about overtaking a decent car, you will be embarassed. The performance usually goes from bad to worse if you add a CNG.
If you are mostly driving in the city and you are looking for a work horse, Alto is a great choice. If your budget allows, I will suggest to go for a swift DX, I think its a quantum leap for 200-300k.