Some people express a preference for the iVMS-4500 App.
It provides access to some features that Hik-Connect does not, such as being able to arm/disarm detection/alerting from within the App.
By all means test it for yourself.
Hikvision rarely mention iVMS-4500, I have no insight into their long-term plans for that App - I suspect that Hik-Connect is updated more frequently.