the program is not gonna kill my os?

you'd better tell us your own opinion first. how much did it help you? if you've got good results keep using it, if it's not good why do you need our opinions?

I suggest you try a very good English learning game called Essential Grammar by Raymond Murphy. ;)

Hello Валерий,

You know, I have studied English long enough to find my own way of learning. It is not so much that my way is the best in the world – actually not – but it is the best for me. I rooted myself in it and I am quite averse to any big change. That’s why I didn’t download that software. However it didn’t stop me from reading its futures on the site. So I have some thoughts to share with.

Disadvantages
1)looking so ever tangled (a lot of options, modules to install, fuzzy manual, etc)
2)having no modules to improve your writing and grammar.

Advantages
1)module creating
2)voice recording
3)visual displaying your pronunciation and comparing it with the original.

I had no task to examine every feature of it. So, I mentioned only things I liked and disliked most of all. Again, I didn’t download it. So, it may be buggy in use.

All in all, if you like that software, be able to install it, have no better alternative, then it is worth using. Anyway, it is not enough to learn English.