I've got to say I'm not really impressed with MasterTopik. Like you I'd seen that the videos after the beginner level, were in Korean only. The videos you can see for free seem great, you think you're going to learn new stuff, but actually, for most of the expressions and words that they use, that I do not already know, in the other paid for videos, the teacher just waits a second, does an mmm... sound, like we know what the word means, and then just goes on! Things are not explained properly, as if the teacher was unable to realise that the expression or word needed explanation.
So I know, it seems exciting, you're thinking, awesome, that's a full list of stuff organised for me, but in the end you will have to spend time online to research on the explanations that are missing in the class for you to actually understand the expression you are learning.
Plus you *have* to use Internet Explorer on Windows to just about get a 100% read on the video the first time round (it's needed to get the additional 6 months) because the player doesn't work well on other devices. You can still use it on Android/iPad, but any issue, they just tell you you have to use IE on windows... it's 2020 FFS. Also this player I've been told will prevent you form recording the videos (inc from screen recorders) so don't think it'll be easy to just keep the videos for later.
That said, if you like being really lazy, you can just listen, grab what you want from a video and are ok with not understanding the lacking explanations, it's better than nothing. They also send you textbooks separate from the video classes, that are great because again it's mostly in Korean, it's got colours and it reaches a fairly high level - I am starting using them to check the level of my current comprehension, and see if I can learn words from context at my current level. The cost of shipping is insane, but they reach you in 10 days in Europe, and they're exciting shiny new things. All in all (this post has become a review now!) I don't regret too much buying the course (considering the cost of going to local classes and the fact that you can jump level any time, perfect for self-learners), but know that you will get frustrated with a few things... The free videos made me imagine much better than what the videos are in reality.