If VI have good coverage in your area then go ahead otherwise note that VI don't have proper VOLTE and no Vowifi and then regular outages with no proper reason atleast in my area @Hyderabad.
Vi is amazing in my area followed by Airtel and Jio. But it would depend upon your area as well. Jio is very clogged here now-a-days unlike earlier making Vi a decent alternative for me with Double Data for the time being.
VoLTE works. If it doesn’t, call customer care and get it activated. Last week I ported from Jio to Vi and couldn’t be more happier. Jio speeds were 0.10 Mbps and Vi gives me 70-80 Mbps. Jio is a scam network with fancy ads and oversubscribed.
I challenge you to use Jio’s wifi calling for one week and make a note of how many callers tell you your phone was out of coverage even when you had full wifi signal.
I have disabled Jio and Airtel’s wifi calling as it is simply unusable and unreliable. You will miss important calls.