First of all I want to say that like another sim Jio is also a normal sim so don’t afraid to purchase it.
Now disadvantages
As I am using Jio so according to me network capacity is a factor that unsatisfy the users.
If the network is full then your Internet will run as fast as describe with 4G speed till the limit ( that is 4GB) .
Calling on another network is also a problem .
Mostly when we call to a BSNL user , call may be connect otherwise no. But call on Reliance , Telenor , Airtel , Aircel all are connect immediate .
I want to say that Go for Jio.
There are some problems but not huge problems.
Thanks for reading.