Frankly, It depends on what you are looking for. In my personal situation, I have found different tutors/teachers with different methodologies to help me with my English skills. They have helped me with my pronunciation, rules grammar and also my speaking skills. But being honest, the most important thing/task is to be "a good student". I mean, we need to continue studying English for ourselves even if we don't have time/money to schedule a lesson on Italki :)
I’ve had good experiences with using community tutors just for chat, since I already know the language, but I do have reservations about whether one can learn a foreign language from scratch using even a professional teacher on an online website. I personally would have more confidence in a traditional classroom environment where you have teachers and other students to converse with. But, using tutors or professional teachers here would be a great supplement to a traditional classroom environment.