I have tried many quiz components but this is the one that I'm going to use because it is very professional, matches almost all the needs, though there is room for improvement concerning other useful functions which are not yet in it. I'm not saying this because I'm not 100% satisfied with the product. I am. These features I hope will be in later editions but no one should have doubts, that's the best in the market.
The support is also great, I always got detailed help if a question, some modifications just came up. One thing is that I didn't get answer right away, perhaps because of some curiosity of their ticketing system. I would have preferred immediate answers, that is an answer within a working day. Sometimes it took 2 days, but it is also true that I did not pay for the improved support service. All in all, support was always very good and when I asked for some custom development, e.g. to modify the component according to my needs, they did their best and I feel it was worth paying for.
All in all, the component is rock-solid, runs perfectly, has got many options and it looks great. It is also a good feature that you can make your tests or quizzes free or paid.
I can recommend it, it does what it says it does.