I just got the Eustachi yesterday. Even if it doesn't completely end the tinnitus, but cleans out my tubes and relieves that fullness feeling which I get several times a day, I'll be quite satisfied with the purchase.
I have not tried one, but think that the Otovent balloon method works basically the same way as the Eustachi and similar devices, by gently blowing air in the nostril(s) while you swallow.
I'm also getting a facial steamer later today, with a nose/mouth inhaler attachment, as I have heard this can also help to open and unclog the Eustachian passages.