From my limited listening, I have relatively found Saberi to have the best tonal quality and better singing... I have not liked any other girl at all (including Poonam) here.
After listening to the performances of all female singers again from my recordings, my opinion---and others may differ here---is that Saberi, perhaps, is the best female singer of the show. She has a heavy but sweet and melodious voice that is very well trained. By making it little husky she can sing the item numbers very well... and at the same time by making it softer she can sing soft melodies also as well. This was the case with her 2 performances in the last round. I would highly like to see her back in the race with Brahmastra. Fortunately, she has mentors in VS who would not let her voice fade away in any case and will make the best use of it - in films or otherwise for their VS label.