This is a well put together film, the storyline itself is not original... everyone wants the secret. However the Spanner concept is quite interesting and the actors portrayal of themselves as Spanners moving around a world of different mortality's worked well. Their lack of interest in the idea beyond the specifics of each individuals ability allowed you to explore past the oooh bit a lot of special ability films stop at.It gave the film a few more layers of interest and complexity.
There are two things that stop this film hitting an 8, the first is it is an unfortunately bad title; In Britain, at least, a spanner is not a positive description of another individuals ability to cogitate so film full of meaningful intense people striding around darkly and calling each other "spanners" does detract a little.
The support cast was a bit light in the acting skills department at times but the leads were solid and competent. The film was dark at points, some suspense, a hint of humour and enough philosophy ( not quite star trek but...) and enough thinking about being different.
Good solid Sci-fi, easy to watch and entertaining, blockbuster it ain't but better for it. What I liked was seeing the limited budget for special effects actually put to work work effectively, the real was stretched rather than turned into a Day-Glo nightmare. Apart from the Trogs (which are the second reason this film is not an 8).