I used it previously then switched to RethinkDNS.
I like the blocking abilities and the logging more with RethinkDNS. I never used I2P so that was moot for me.
With RethinkDNS I can pick the Hagezi blocklist and No Facebook, as an example, quite easily. I can also individually block domains and IPs. Dnscrypt doesn't allow that much precision.
It also has features like allow/disallow only on WiFi or data, block apps not in use, block all apps when device is locked, plus a bunch more stuff.
It integrates with Orbot, but Orbot must also be installed.
Really I can't say anything bad about InviziblePro, I prefer RethinkDNS, you might not though.