As is fast becoming tradition in this area, the game comprises several mini-games (most of which are unlockable as you go along), which you play for a while each day, to build up your score. Each mini-game involves a series of words, sometimes needing you to guess the missing letter, or match words to definitions, and so on. After a couple of games, it seemed to gauge my level well enough to provide a comfortable mix of vocabulary, such that I was confident with just over half, familiar with most of the rest, and encountered a handful of totally new words from time to time.
A particular feature I like comes at the end of each mini-game: you are shown a list of the words you saw during that round, and you can scroll up and down the list to see the definition of each one. Any words you got wrong during the round are shown at the top with little crosses beside them, so you can easily spot problem areas when you encounter them. I have not yet seen any longer-term reporting regarding particular words (e.g. a word you consistently get wrong), but maybe it's there and I haven't found it or unlocked it yet.
"My Word Coach" definitely has a certain character of its own, so it is not entirely leeching off its fore-runners in the field. However, there are areas where it lacks a little. For example, the handwriting-recognition is not perfect (at least seemingly not as sophisticated as the Kawashima games), and the graphical style as a whole seems a little bit dated. However, these things don't really hinder the process, and I have certainly had my vocabulary taxed a little by it so far.
Conclusion? Best not to draw any final thoughts just yet, since I have only played it for a couple of hours, but my impressions so far are pretty good overall. I am certainly all in favour of any way to improve the nation's dwindling competence in literacy, and given the recent successes of the Kawashima games at schools up North (Scotland), perhaps this is one effective way to do it.
Slightly Pointless Addendum:
Being the pedant that I am, I will have to take this opportunity to quibble on a couple of words I have seen in the game thus far. Firstly, it defines a "centurion" as a Roman guard in command of 100 soldiers, when in actual fact it was really only 80 or so most of the time. And secondly, it defines "Armageddon" as the final war between good and evil mentioned in the Bible. Well, it's close... Armageddon is actually the place where the battle will occur, according to Revelation 16:16.