I did italki for around 2 years between the stints when I lived in Japan, and I found that it improved my comfort level with speaking dramatically. My tutor did not provide me with highly structured lessons; each weekly conversation was simply free dialogue, so it really was just to exercise my speaking muscle, rather than rigorously learn vocabulary or grammar structures.
If you are in a spot where you feel like your passive vocabulary is significantly larger than your active vocabulary, it might be worth giving it a try. I would describe my experience with italki as mostly positive, and I have recommended it to my friends.