It doesn’t teach you grammar…
but a bit of research on the internet or at the library goes a long way here.
I’ve found Michel Thomas’s method to be particularly helpful when it comes to grammar. You can download a free booklet of his courses (no audio) here.
Margarita Madrigal used a similar method to teach grammar.
You may have to find someone to practise with.
Not really a disadvantage though – rather an opportunity to meet new people. In a multicultural city like Sydney or Birmingham, it’s actually quite easy to find people who speak almost any language. If you can’t find someone nearby, you might like to consider iTalki.
04 Disadvantages of this method