2. True 4G Speed
3. Largest 4G network in India
You must have seen advertisements from other network providers on TV especially during T20 cricket world-cup, claiming to be the 'largest 4G network in India' or 'Largest 4G network in the world'.
These advertisements are meant to put the words 'largest 4G network' in your brains, so that when Jio comes out and they claim to be the largest 4G network, people won't believe them. This is probably the only way for these network providers to survive as they have really small network coverage.
But, when Jio gets launched, it's coverage is said to be bigger than 2G coverage of most other players! Jio will have 4G network coverage at over 1.02 lakh villages and 18,000 towns in their first phase. Currently 4G is available to less than 15% of India's population and Jio will cover 70% of India at launch. They plans to cover 90% of India with 4G by 2017 and all of India by 2018.
4. Huge investment
They have invested over Rs 150,000 crore into this project. Just to put things into perspective,
In the last couple of years, JIO has already spent almost as much as the major incumbent telecom firms, like Bharti Airtel Ltd, Idea Cellular Ltd and Vodafone India Ltd, have spent over the past more than 20 years of being in operations. 
This is good for India's economy and at the same time provide a good service to millions of people. This forces other players to invest more into their own infrastructure. Airtel have already announced that they will invest 60,000crore in modernizing their network. [
5. VoLTE (calls send as data)
Jio is the only company in India to use VoLTE technology. 4G is exclusively designed for high speed data transfer and it cannot handle normal mobile calls. To solve this issue, other players switch to 3G/2G whenever a call is made. Since Jio doesn't have 2G/3G, they send calls as data through 4G itself. This is similar to skype calls but probably in much better quality. 
Many people will get access to good quality video calls for the first time in their lives.
6. Largest fiber optic network in India
They have laid 250,000+ KMs of high quality fiber optic cable and have installed over 90,000 eco-friendly 4G towers. And, Jio is using cables of 288 fibers or 96 fibers in most places while other players have cables with only 12-24 fibers. More fibers means, they will have more bandwidth and more speed.
This is an unprecedented feat in Indian mobile network industry. Most other companies do not lay such large amount of cables, instead they depend on agreement with various other companies who own fiber networks. Apart from this, Jio also have access to the cables laid by Reliance communications.
The best way for Jio to attract maximum users is to provide plans which are much cheaper than other players. And, since they have a new empty network designed to handle millions of users, they will be able to provide unbelievable promotional plans atleast for the first 2 years.
In short Jio has defined new way to Telecom Industry.
From User Perspective here are few FAQsDoes my 4g Mobile support Jio 4G Sim
Well, Reliance Jio is going to provide 4g service through three different bands: Band 5 (850MHz), Band 3 (1800Mhz) and and band 40 (2300MHz). Band 40 will remain active PAN India but rest of two bands will be available in few circles and later Jio will expand as usual. Be sure your 4G device supports at least two bands – 2300MHz and 1800Mhz or 850Mhz to get high-speed 4g service from RJIO.
You can always use Jio sim if your mobile supports any of three LTE Bands: 3, 5 & 40 – You can check vendor site for band availability in your 4g phone.
What is VoLTE ?
VoLTE is the short form of Voice over LTE which means true HD Voice calling over 4G LTE Network. Voice call would become accurate & clearer. 4g mobile must support VoLTE features to make HD Voice calls.
What is VoWiFi ?
VoWiFi stands for Voice over WiFi. 4G mobile users can continue HD Voice calls over WiFi of same telecom network if 4G Cellular networks remain weak. Switching between VoLTE & VoWiFi works in background without disruption running HD Voice calls.
In current scenario, Jio 4G is present almost every corner in India, VoWFi becomes less priority in most cases.
I have 4G mobile but it doesn’t support VoLTE, Can I access Jio 4G data ?
No matter your 4g phone supports VoLTE or VoWiFi or not, you can still access data services using Jio 4g sim both in Home & Roaming circle.
How to check VoLTE support in 4g mobile ?
Just insert Jio sim in you 4g mobile & be sure you are in a place where Jio 4g network availability is strong – Just wait till network come – If phone supports VoLTE – you will get a VoLTE sign just above mobile tower icon on upper left/right corner of mobile screen. You may also get LTE HD sign for true HD calls.
How to know which 4g mobiles support VoLTE ?
Only VoLTE supported mobiles will get access to true HD Voice call from Reliance Jio 4g network. Additional settings & updates will come from Reliance Jio & phone vendor side.
How make HD Voice & Video calls when 4G phone doesn’t support VoLTE ?
VoLTE is software based features which 4G mobile companies or networks need to send to device as an update file to activate & enable it for end users. Alternatively, you can use Jio-join app for HD Voice & Video call, if VoLTE is missing in your 4g handset.
VoLTE supported Android mobiles
Android phones with following Qualcomm Snapdragon Processor would come under VoLTE support list: 210, 400, 410 412, 415, 430, 615, 616, 617, 618,620, 650, 652, 800, 801, 805, 808, 810 and 820, 823. Be sure your VoLTE supported 4G mobile is on Android 5.1 as it offers customized settings for VoLTE.
VoLTE supported iOS devices
iPhone 6, iPhone 6 Plus, iPhone 6S, iPhone 6s Plus etc.
Official list of 4g Mobiles supporting Reliance Jio VoLTE service
Please - Click Here to Get the List of Phone Supports Jio