CNG Vs LPG Vs Diesel Vs Petrol-Economy, Performance & maintenance ?

There are good readers who are experienced in automobile. Is there a comparison of these fuels, seperately on the scale of Economy, Performance & Maintenance? We can give marks out of 10. Let's start I will join soon pals!

I could find a one at :

http://www.team-bhp.com/forum/modifying-car/22225-article-cng-vs-lpg-comparision.html

Is an average of 14-15 KM/KG of CNG for an one yr old Alto, which mostly runs in Noida with its AC on in summer is alright? During Feb-March, I used to get an average of 19-20 KM/KG of CNG.

Can you please give a comparisson between CNG and diesel car, in terms of car performance? I am planning to buy a new car in the range of 4-6.5 lakh. I stay in Delhi where CNG is widely available, so i can go for a CNG car with the only condition that the performance and maintenance of car is not hampered due to CNG. I drive about 12,000 kms/year. I am analysing it for long term (7-8 years). Kindly advise. My considerations are: Maruti Ritz, Toyota Liva, Maruti Swift Dzire, Honda Brio, Toyota Etios, Maruti Swift, and Skoda Fabia. Else you can also recommend.