I have vodafone 4G network and I use this network in iphone 6S and vidafone's net is veryy smooth and so fast.
I allmust use 5 hour only youtube and its buffring free network and feel like awesome.
I prefaire only vodafone because its verry fast and many type of offer like I have, 347 rs. Plan and its giving daily 1GB 4G net and unlimited calling free, validity 28 days and its good offer for your work and your time pass. Like youtube, facebook, instagram, twitter, snapchat, whatsapp, hike and etc.
