Great concept, engaging cast, excellent production (for its time)... It all added up to much less than it could have, but was still very watchable if you took it with a grain of salt.
I had the feeling that the original intent was to do a truly 'realistic' space show, and that someone chickened out. It seemed like as soon as the first ratings came in, undoubtedly low, increasingly fantastic elements started to creep in to the series. These were fun, but more of a nod to the Doctor Who crowd than at all consistent with the original premise of Space Island One: life on a space station.
Still, I found the series to be an important 'island' of innovation in a perpetually childish and overwrought TV SF landscape. If you want to see a better show built on similar lines, try to track down the 1980s series Star Cops. Or the 1970s series Moonbase 3. Clearly, these low-key SF tend to come out of the UK every decade or so... We're overdue for another!