http://wajcun6t3tqaxrxopfqmvjwbojabns4r3c4icclj72eik74ooldmryyd.onion
(For example, Dino does not handle onion/i2p addresses, gajim works with DMs and MUCs, but fails with file download) Slow connection, mostly with sharing files. (In monocles chat, for example, I frequently got “timeout error” when trying to send videos, but maybe this can be fixed setting a higher timeout when using tor and i2p in their source code) You need some kind of knowledge to setup this, and a hardware running 24/7.