Is Mr. Jack a balanced game, or do experienced gamers tend to win more often with either the Inspector or Jack the Ripper?
Excellent question: I play it a lot, often with the same people (my wife, family, friends). It's one of the few games for two that I really enjoy.
To answer your question, maybe we haven't fully explored the possible strategies, but we find that the game is quite biased in favour of the Inspector. Other people who have played with us seem to agree. Also, I discovered while browsing the web that there are extensions (referred to here, for example) that make the game more balanced.
On a related note, while Jack sometimes win, I have only once seen him win by escaping (and that was because of a terrible mistake made by the Inspector). All the other times I've seen Jack win, it was by reaching the last turn, or by the inspector accusing someone at random because time was short anyway.