Prepaid mobile plans are better according to me as they are cheaper and you can have better controlled calling.
Prepaid mobile plans are very suitable and beneficial to younger users and students. You are charged as you use so there is no late fees and other miscellaneous charges added on.
Prepaid are easier to buy then to get a postpaid connection which involves a lot of documentation and credit checks. If you say post paid are better for emergencies as prepaid calling is enabled only if you have balance then well you can keep an extra recharge card but today vodafone offers this new facility called VX credit where you can recharge with just a text message in emergency.
Prepaid mobiles have a lot of offers these days like 20% extra on recharge free call time and others, also if you have another exiting new service provider switiching would be easier on prepaid.
Prepaid can be cheaper to you if you have irregular pattern of making calls like one month you make a lot of calls and another month you make very few calls, in post paid you will have to pay fixed charges irrespective of use.