I own both and haven't used my grand since I got the VV versions. I still occasionally use my mini for stealth/travel.
I also switched to a Reomizer RBA which the VV helps me not worry about the resistance of the coil, I just adjust the voltage to suit my taste.
I'm not sure it has a deeper juice well, they look the same to me. Advantages of the Grand are it is less expensive, shorter, washable and uses only one battery. VV Grand wins on consistency of vape and flexibility with an array of resistance and juices.