I would repeat

I arrived in China without being able to say a single word in Chinese and after 5 months I have finished HSK3 level thanks to the help of my professor.
One to one classes add lots of value to students as you can improve your pronounciation and speaking easier than if you go to a group classes. In addition, they are always willing to answer your questions after class through WeChat, so if you are doing your homework and need help you won't have problems as they are always nice to provide it.
XMandarin takes care of you and prepares a schedule that fits you. If you need to change a class one day due to personal reasons they will rearrange it and it won't be a problem. Really happy about having chosen them to study chinese.
As said before, I recommend and I would repeat it.